A method and system for producing high purity sodium hydrosulfide

Abstract

The application relates to the technical field of hydrogen sulfide preparation equipment, in particular to a method and system for preparing high-purity sodium hydrosulfide. The system takes sulfur-containing hydrogen sulfide acidic gas as raw material, controls the generation of impurities through one of a steam contact section, a first gas-liquid contact section, a second gas-liquid contact section and a third gas-liquid contact section, deeply absorbs and controls the escape of hydrogen sulfide through a horizontal gas-liquid reactor of a two-section combined reaction part, and circulates and uses sodium-containing alkaline liquor introduced by a boundary sodium-containing alkaline liquor introduction pipe of a two-section circulation part, so as to reduce the exogenous impurities of the sodium-containing alkaline liquor, accurately control and prevent the reaction imbalance between the sodium-containing alkaline liquor introduced by the boundary sodium-containing alkaline liquor introduction pipe and the acidic gas discharged by the one-section combined reaction part, finally realize the preparation of high-purity sodium hydrosulfide and the synchronous realization of low-sulfur hydrogen sulfide content purified tail gas emission, and the system does not need to additionally add impurity removal reagents or tail gas treatment reagents, and conforms to the design concept of green chemical industry.

Description

Technical Field

[0001] This application relates to the field of hydrogen sulfide preparation equipment technology, and in particular to a method and system for preparing high-purity sodium hydrosulfide. Background Technology

[0002] Oil refineries primarily employ processes such as the Claus sulfur recovery method and wet sulfuric acid production to treat hydrogen sulfide-containing acidic gases generated during production. The Claus sulfur recovery method typically involves: Claus sulfur preparation, Claus tail gas treatment (SCOT), solvent regeneration, tail gas incineration, and flue gas treatment. This process is lengthy, complex, and requires significant investment. The wet sulfuric acid production process includes acidic gas incineration, SCR denitrification, SO2 catalytic conversion, hydration condensation, and tail gas treatment. However, this process demands stringent operating conditions and struggles to produce high-value fuming sulfuric acid, resulting in poor economic returns. In contrast, the sodium hydrosulfide production process offers advantages such as a simpler process and lower operating costs, effectively treating hydrogen sulfide-containing acidic gases generated during oil refining and chemical production. Furthermore, this sodium hydrosulfide production process generates sodium hydrosulfide, which has a wide range of applications, such as: in the dye industry for the synthesis of organic intermediates; in the leather industry for dehairing and tanning raw hides; in the fertilizer industry for removing monomeric sulfur from activated carbon desulfurizers; and in the production of synthetic fibers for dyeing with sulfurous acid. Additionally, sodium hydrosulfide is also a raw material for the preparation of products such as ammonium sulfide, sodium polysulfide, and sodium thiosulfate.

[0003] However, if the hydrogen sulfide-containing acidic gas produced by oil refining and chemical industry is to be used as a raw material in the sodium hydrosulfide production process, a complex pretreatment operation is required to remove the impurities from the hydrogen sulfide-containing acidic gas. For example, a pretreatment process for purifying hydrogen sulfide (H2S) in acidic gas using a two-stage absorption-two-stage regeneration process is as follows: The hydrogen sulfide-containing acidic gas first comes into countercurrent contact with a first-stage lean amine solution in a first-stage absorption tower. The first-stage lean amine solution selectively absorbs the hydrogen sulfide from the acidic gas, resulting in a first-stage rich solution. This first-stage rich solution then enters a first-stage regeneration tower for regeneration. The first-stage regenerated gas from the top of the first-stage regeneration tower enters a second-stage absorption tower and comes into countercurrent contact with a second-stage lean amine solution. The second-stage lean amine solution absorbs the hydrogen sulfide from the first-stage regeneration gas, resulting in a second-stage rich solution. This second-stage rich solution then enters a second-stage regeneration tower for further regeneration. The gas at the top of the second-stage regeneration tower is the purified hydrogen sulfide gas. Finally, the purified hydrogen sulfide gas is neutralized with a sodium-containing alkaline solution to form sodium hydrosulfide. However, this two-stage absorption-two-stage regeneration process is relatively complex, with high equipment and operating costs, and the purity of the final sodium hydrosulfide product is low. In addition, in order to reduce the amount of by-reaction products generated in sodium hydrosulfide products, it is necessary to produce sodium hydrosulfide by reducing the conversion rate of hydrogen sulfide. However, the conversion rate of sodium hydrosulfide obtained by this method is only 68.58% to 97.20%, and the volume fraction of hydrogen sulfide in the exhaust gas (excluding air) is as high as 22.30% to 66.81%, which is difficult to be directly emitted. Summary of the Invention

[0004] This application provides a method and system for preparing high-purity sodium hydrosulfide to solve the following technical problem: how to simultaneously reduce the impurity content of sodium hydrosulfide prepared from hydrogen sulfide-containing acidic gas and the hydrogen sulfide content in the exhaust gas. In a first aspect, embodiments of this application provide a system for preparing high-purity sodium hydrosulfide, the system using hydrogen sulfide-containing acidic gas as raw material, the system comprising: A combined reaction section includes a vertical reaction separation device, a steam contact section, a first gas-liquid contact section, a second gas-liquid contact section, and a third gas-liquid contact section. The steam contact section is located at the bottom of the vertical reaction separation device. The first gas-liquid contact section is located above the steam contact section, the second gas-liquid contact section is located above the first gas-liquid contact section, and the third gas-liquid contact section is located above the second gas-liquid contact section. This divides the internal space of the vertical reaction separation device into a stripping zone, a first-stage reaction zone, a second-stage reaction zone, and a third-stage reaction zone. The vertical reaction separation device includes a raw material inlet for conveying hydrogen sulfide-containing acidic gas, and the raw material inlet is located on the lower side wall of the first-stage reaction zone. A circulation section includes a primary sodium-containing alkaline solution inlet, a secondary sodium-containing alkaline solution inlet, a tertiary sodium-containing alkaline solution inlet, a secondary circulation pump, and a tertiary circulation pump. The primary sodium-containing alkaline solution inlet is located at the upper end of the first gas-liquid contact section, the secondary sodium-containing alkaline solution inlet is located at the upper end of the second gas-liquid contact section, and the tertiary sodium-containing alkaline solution inlet is located at the upper end of the third gas-liquid contact section. The primary, secondary, and tertiary sodium-containing alkaline solution inlets are used to respectively supply sodium-containing alkaline solutions to... Sodium-containing alkaline solution is introduced into the first-stage reaction zone, the second-stage reaction zone, and the third-stage reaction zone; the inlet of the second-stage circulation pump is connected to the outlet of the second-stage reaction zone in the vertical reaction separation device via a pipeline, and the outlet of the second-stage circulation pump is simultaneously connected to the inlet of the first-stage sodium-containing alkaline solution and the inlet of the second-stage sodium-containing alkaline solution; the inlet of the third-stage circulation pump is connected to the outlet of the third-stage reaction zone, and the outlet of the third-stage circulation pump is connected to the inlet of the second-stage circulating alkaline solution and the inlet of the third-stage sodium-containing alkaline solution. The two-stage combined reaction section includes a horizontal gas-liquid reactor, a first partition, a second partition, a second-stage primary gas chamber, a second-stage secondary gas chamber, a second-stage tertiary gas chamber, a second-stage primary ejector, a second-stage secondary ejector, a second-stage tertiary ejector, and a liquid collection chamber. The first partition and the second partition divide the horizontal gas-liquid reactor into a two-stage primary reaction zone, a two-stage secondary reaction zone, and a two-stage tertiary reaction zone. The air inlet of the second-stage primary ejector is connected to the top air outlet of the vertical reaction separation device, the discharge outlet of the second-stage primary ejector is connected to the feed inlet of the second-stage primary reaction zone, and the air outlet of the second-stage primary reaction zone is connected to the liquid collection chamber. The air inlet of the second-stage primary gas tank is connected to the air inlet of the second-stage secondary ejector. The outlet of the second-stage secondary ejector is connected to the inlet of the second-stage secondary reaction zone. The outlet of the second-stage secondary reaction zone is connected to the air inlet of the second-stage secondary gas tank. The outlet of the second-stage secondary gas tank is connected to the air inlet of the second-stage tertiary ejector. The outlet of the second-stage tertiary ejector is connected to the inlet of the second-stage tertiary reaction zone. The outlet of the second-stage tertiary reaction zone is connected to the air inlet of the second-stage tertiary gas tank. The liquid collection bag is located in the middle of the bottom of the horizontal gas-liquid reactor. The two-stage circulation section includes a boundary sodium-containing alkaline solution inlet pipe and a two-stage circulation pump. The outlet of the boundary sodium-containing alkaline solution inlet pipe is simultaneously connected to the inlet of the first-stage ejector, the inlet of the second-stage ejector, and the inlet of the third-stage ejector. The inlet of the two-stage circulation pump is connected to the outlet of the liquid collection bag, and the outlet of the two-stage circulation pump is connected to the inlet of the first-stage ejector, the inlet of the second-stage ejector, the inlet of the third-stage ejector, and the inlet of the third-stage reaction zone.

[0005] Optionally, the combined reaction section further includes: a downcomer, a first riser, and a second riser. The downcomer is fixedly connected between the steam contact section and the first primary reaction zone. The first riser is fixedly connected between the first primary reaction zone and the second secondary reaction zone. The second riser is fixedly connected between the second secondary reaction zone and the third tertiary reaction zone.

[0006] Optionally, the vertical distance between the bottom end face of the downcomer and the top end face of the steam contact section is 100mm to 300mm; and / or The height difference h1-h2 between the length h1 of the first riser pipe located inside the first stage of the secondary reaction zone and the highest liquid level h2 inside the first stage of the secondary reaction zone is 100mm to 300mm; and / or The height difference h3-h4 between the length h3 of the second gas riser pipe located inside the first stage of the three-stage reaction zone and the highest liquid level h4 inside the first stage of the three-stage reaction zone is 100mm to 300mm.

[0007] Optionally, the combined reaction section further includes: a first rainproof cap and a second rainproof cap, wherein the first rainproof cap is fixedly connected above the first air riser, and the second rainproof cap is fixedly connected above the second air riser. The bottom outer diameter of the first rainproof cap is 1.2 to 1.4 times the outer diameter of the first air riser, and the bottom outer diameter of the second rainproof cap is 1.15 to 1.35 times the outer diameter of the second air riser.

[0008] Optionally, the cross-sectional area of ​​the first riser pipe is 15% to 35% of the cross-sectional area of ​​the vertical reaction separation device; and / or The cross-sectional area of ​​the second riser pipe is 15% to 35% of the cross-sectional area of ​​the vertical reaction separation device.

[0009] Optionally, the circulation section further includes a secondary cooler, a tertiary cooler, and a product cooler. The secondary cooler is connected in series to the outlet of the secondary circulation pump, the tertiary cooler is connected in series to the outlet of the tertiary circulation pump, and the product cooler is connected in series to the outlet of the vertical reaction separation device.

[0010] Optionally, the combined reaction section further includes a demister, which is fixedly connected to the top of the vertical reaction separation device.

[0011] Optionally, the two-stage combined reaction section further includes a two-stage cooler, which is connected in series with the outlet of the two-stage circulating pump.

[0012] Optionally, the system further includes: The control unit includes a level controller, an online hydrogen sulfide analyzer, a boundary alkaline solution mass flow regulating valve, and a secondary discharge alkaline solution mass flow control valve. The level controller is installed inside the horizontal gas-liquid reactor to control the alkaline solution level in the reactor. The online hydrogen sulfide analyzer is installed at the outlet of the second-stage tertiary gas manifold. The boundary alkaline solution mass flow regulating valve is installed at the outlet of the boundary sodium-containing alkaline solution inlet pipe. The secondary discharge alkaline solution mass flow control valve is installed at the outlet of the second-stage circulating pump. The secondary discharge alkaline solution mass flow control valve is connected to the level controller via an electrical signal, and the online hydrogen sulfide analyzer is connected to the boundary alkaline solution mass flow regulating valve via an electrical signal.

[0013] Optionally, the two-stage combined reaction unit further includes: a two-stage primary distributor, a two-stage primary baffle, a two-stage secondary distributor, a two-stage secondary baffle, a two-stage tertiary distributor, and a two-stage tertiary baffle; the two-stage primary distributor is fixedly connected to the discharge port end of the two-stage primary injector, the two-stage primary baffle is fixedly connected to the inlet end of the two-stage primary air manifold, and the discharge port end face of the two-stage primary distributor is spaced apart from the vertical surface of the two-stage primary baffle; the two-stage secondary distributor is fixedly connected to the two-stage primary air manifold. At the discharge port end of the second-stage injector, the second-stage baffle is fixedly connected to the air inlet end of the second-stage air manifold, and the discharge port end face of the second-stage distributor is spaced apart from the vertical surface of the second-stage baffle; the third-stage distributor is fixedly connected to the discharge port end of the second-stage injector, and the second-stage baffle is fixedly connected to the air inlet end of the second-stage air manifold, and the discharge port end face of the third-stage distributor is spaced apart from the vertical surface of the second-stage baffle.

[0014] Optionally, the discharge direction of the two-stage primary distributor is at an angle of 30° to 60° to the vertical plane of the two-stage primary baffle; and / or The discharge direction of the two-stage secondary distributor is at an angle of 30° to 60° to the vertical plane of the two-stage secondary baffle; and / or The discharge direction of the two-stage secondary distributor is at an angle of 30° to 60° to the vertical plane of the two-stage secondary baffle.

[0015] Optionally, the bottom of the first partition and the second partition are respectively provided with slots to allow the sodium-containing alkaline solution in the two-stage primary reaction zone, the two-stage secondary reaction zone and the two-stage tertiary reaction zone to flow through the slots; the opening angle of the slots is 30° to 120°.

[0016] Secondly, embodiments of this application provide a method for preparing high-purity sodium hydrosulfide, the method being adapted to the system described in the first aspect, the method comprising: A first-stage sodium-containing alkaline solution is subjected to a first neutralization reaction with a hydrogen sulfide-containing acidic gas to obtain a first-stage pure gas and a first-stage effluent alkaline solution. A second neutralization reaction is carried out between a secondary sodium-containing alkaline solution and the first purified gas to obtain a second purified gas and a secondary effluent alkaline solution. A portion of the secondary effluent alkaline solution is returned to the first neutralization reaction and recycled as the primary sodium-containing alkaline solution. A third neutralization reaction is carried out between a first-stage tertiary sodium-containing alkaline solution and a second-stage purified gas to obtain a third-stage purified gas and a first-stage tertiary effluent alkaline solution. A portion of the first-stage tertiary effluent alkaline solution is returned to the second neutralization reaction for recycling as the first-stage secondary sodium-containing alkaline solution. Another portion of the first-stage tertiary effluent alkaline solution is returned to the third neutralization reaction for recycling as the first-stage tertiary sodium-containing alkaline solution. The first-stage alkali solution, all the remaining second-stage alkali solution, and all the remaining third-stage alkali solution are mixed to obtain the first-stage alkali solution. The primary effluent alkaline solution is stripped to obtain a sodium hydrosulfide solution; The sodium-containing alkaline solution in the boundary area and the third purified gas are subjected to a two-stage multi-stage injection to obtain a secondary output alkaline solution and purified tail gas.

[0017] Optionally, the temperatures of the first neutralization reaction, the second neutralization reaction, and the third neutralization reaction are all between 50°C and 75°C, the pressures of the first neutralization reaction, the second neutralization reaction, and the third neutralization reaction are all greater than or equal to 0.10 MPa, and the reaction times of the first neutralization reaction, the second neutralization reaction, and the third neutralization reaction are all between 0.5 seconds and 90 seconds.

[0018] Optionally, the stripping temperature is between 110°C and 185°C, and the stripping pressure is greater than or equal to 0.10 MPa.

[0019] Optionally, the step of subjecting the sodium-containing alkaline solution in the boundary area and the third purified gas to a two-stage multi-stage injection to obtain a secondary effluent alkaline solution and purified tail gas includes the following steps: The sodium-containing alkaline solution in the boundary area is divided into the first boundary area sodium-containing alkaline solution, the second boundary area sodium-containing alkaline solution and the third boundary area sodium-containing alkaline solution. The sodium-containing alkaline solution in the first boundary area and the third pure gas are subjected to a two-stage first-stage injection to obtain a two-stage first-stage discharge alkaline solution and a two-stage first-stage tail gas. The sodium-containing alkaline solution in the second boundary zone and the first-stage tail gas in the second stage are injected in a second stage to obtain a second-stage discharge alkaline solution and a second-stage tail gas. The sodium-containing alkaline solution in the third boundary zone and the second-stage tail gas are subjected to a second-stage tertiary injection to obtain a second-stage tertiary discharge alkaline solution and purified tail gas. The first-stage, second-stage, and third-stage alkali solutions are mixed to obtain a second-stage alkali solution; wherein a portion of the second-stage alkali solution is returned to the first-stage, second-stage, or third-stage spraying steps for recycling as the sodium-containing alkali solution in the boundary area. All remaining secondary effluent alkaline solution is returned to the third neutralization reaction and recycled as a first-stage tertiary sodium-containing alkaline solution.

[0020] Optionally, the temperatures of the two-stage primary injection, the two-stage secondary injection, and the two-stage tertiary injection are all between 50°C and 75°C, the pressures of the two-stage primary injection, the two-stage secondary injection, and the two-stage tertiary injection are all between 0.3MPa and 3.5MPa, and the reaction times of the two-stage primary injection, the two-stage secondary injection, and the two-stage tertiary injection are all between 0.01s and 0.3s.

[0021] Optionally, the mass flow rate of the sodium-containing alkaline solution in the first boundary region is 0.4 to 0.6 times the mass flow rate of the sodium-containing alkaline solution in the boundary region; and / or The mass flow rate of the sodium-containing alkaline solution in the second boundary region is 0.3 to 0.5 times that of the mass flow rate of the sodium-containing alkaline solution in the boundary region; and / or The mass flow rate of the sodium-containing alkaline solution in the third boundary region is 0.1 to 0.4 times that of the mass flow rate of the sodium-containing alkaline solution in the boundary region.

[0022] The technical solutions provided in this application have the following advantages compared with the prior art: This application provides a system for preparing high-purity sodium hydrosulfide. The system first incorporates a steam contact section and multiple gas-liquid contact sections within a vertical reaction separation device. These sections divide the device into a stripping zone, a primary reaction zone, a secondary reaction zone, and a tertiary reaction zone. In these zones, sodium-containing alkaline solution and hydrogen sulfide-containing acidic gas react to form primary, secondary, and tertiary effluent alkaline solutions containing sodium hydrosulfide. The system utilizes a two-stage circulation pump and a three-stage circulation pump to circulate the alkaline solutions from the first-stage and third-stage reaction zones back to the current stage or the next stage for further reaction. This ensures that the reaction between the sodium-containing alkaline solution and the hydrogen sulfide-containing acidic gas is closer to the optimal stoichiometric ratio for synthesizing sodium hydrosulfide, resulting in a high-yield, high-purity sodium hydrosulfide product. Furthermore, the stripping zone allows for the stripping of the first-stage alkaline solution, separating the gaseous and liquid phase impurities carried in the solution from the sodium hydrosulfide product and improving its purity. Furthermore, the horizontal gas-liquid reactor is divided into a two-stage primary reaction zone, a two-stage secondary reaction zone, and a two-stage tertiary reaction zone by the first and second partitions. Corresponding second-stage primary ejectors, second-stage secondary ejectors, and third-stage secondary ejectors are installed in these zones. These ejectors ensure thorough mixing of the purified gas discharged from the vertical reaction separator and the sodium-containing alkaline solution introduced through the boundary sodium-containing alkaline solution inlet pipe. This allows the sodium-containing alkaline solution introduced through the boundary sodium-containing alkaline solution inlet pipe to continue reacting with the hydrogen sulfide in the purified gas to form the secondary effluent alkaline solution, preventing the escape of hydrogen sulfide from the purified gas. The secondary effluent alkaline solution is then collected through a collection bag and finally circulated by a second-stage circulation pump in the second-stage circulation section. The solution is then injected again into the second-stage primary ejector, second-stage secondary ejector, and second-stage tertiary ejector, allowing the hydrogen sulfide in the secondary effluent alkaline solution and the third purified gas to continue reacting, reducing external impurities in the sodium-containing alkaline solution. Furthermore, the introduction of second-stage primary, secondary, and tertiary gas chambers into the second-stage combined reaction section buffers the third purified gas ejected from the second-stage primary, secondary, and tertiary ejectors. This facilitates the reaction between the hydrogen sulfide in the third purified gas and the sodium-containing alkaline solution introduced through the boundary sodium-containing alkaline solution inlet pipe, and precisely controls and prevents reaction imbalance between the sodium-containing alkaline solution introduced through the boundary sodium-containing alkaline solution inlet pipe and the acidic gas discharged from the first-stage combined reaction section. Ultimately, this simultaneously achieves the preparation of high-purity sodium hydrosulfide and the emission of purified tail gas with low hydrogen sulfide content. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This application provides a schematic diagram of a system structure for preparing high-purity sodium hydrosulfide. Figure 2 A schematic diagram of a first or second partition in a system for preparing high-purity sodium hydrosulfide, provided for an embodiment of this application; Figure 3 A schematic diagram of the distribution hole structure of a two-stage primary distributor in a system for preparing high-purity sodium hydrosulfide, provided for an embodiment of this application; Figure 4 A schematic diagram of the structure between a two-stage primary distributor and a two-stage primary baffle in a system for preparing high-purity sodium hydrosulfide, provided in an embodiment of this application; Figure 5 A schematic diagram of the structure of a system for preparing high-purity sodium hydrosulfide provided in this application embodiment, comprising a primary baffle, a secondary baffle, and a tertiary baffle; Figure 6 This is a schematic flowchart of a method for preparing high-purity sodium hydrosulfide, provided in an embodiment of this application. Figure 7 This application provides a detailed flowchart illustrating a method for preparing high-purity sodium hydrosulfide. Among them, 1-vertical reaction separation device, 11-first stage reaction zone, 111-first gas-liquid contact section, 112-first riser pipe, 113-downcomer, 12-first stage secondary reaction zone, 121-second gas-liquid contact section, 122-second riser pipe, 13-first stage tertiary reaction zone, 131-third gas-liquid contact section, 132-demister, 14-stripping zone, 141-steam contact section, 142-heating evaporator, 2-horizontal gas-liquid reactor, 21-second stage primary reaction zone, 211-second stage primary ejector, 212-second stage primary gas manifold, 213-second stage primary distributor, 214-second stage primary baffle, 22-second stage secondary reaction zone, 221-second stage secondary ejector, 222-second stage... 223-Secondary gas manifold, 224-Secondary stage distributor, 23-Secondary stage baffle, 231-Secondary stage tertiary reaction zone, 232-Secondary stage tertiary ejector, 233-Secondary stage tertiary gas manifold, 234-Secondary stage tertiary distributor, 241-First baffle, 242-Second baffle, 251-Collection bag, 261-Level controller, 31-First stage secondary circulation pump, 32-First stage tertiary circulation pump, 33-Secondary stage circulation pump, 41-First stage secondary cooler, 42-First stage tertiary cooler, 43-Secondary stage cooler, 44-Product cooler, 5-Hydrogen sulfide online analyzer, 6-Boundary zone alkali mass flow rate regulating valve, 7-Secondary stage discharge alkali mass flow rate control valve, 8-Boundary zone alkali inlet pipe. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] The range descriptions used in this application, such as numerical ranges and proportional ranges, include all possible sub-ranges and single numerical values ​​within that range. For example, the range descriptions of "1 to 6" or "1~6" cover all sub-ranges (such as 1 to 3, 2 to 5, etc.) and single numbers (such as 1, 2, 3, 4, 5, 6) between 1 and 6. Unless otherwise specified, the terms "comprising" and others used herein mean "including but not limited to"; relational terms such as "first" and "second" are used only to distinguish different entities or operations and do not imply an actual order or relationship; "and / or" indicates that multiple situations can exist individually or simultaneously; expressions such as "at least one," "multiple," and "at least one" refer to any combination of the corresponding objects, including combinations of single or multiple objects. The proportional relationships involved in this document, such as mass ratios and molar ratios, should be understood as the correspondence between the first and second terms of a proportional formula, according to the order of description. The raw materials, reagents, instruments, and equipment used herein can all be obtained by purchasing from the market or by existing methods.

[0028] Figure 1 An exemplary schematic diagram of a system structure for preparing high-purity sodium hydrosulfide according to an embodiment of this application is shown; like Figure 1 As shown in the embodiments of this application, a system for preparing high-purity sodium hydrosulfide is provided. The system uses hydrogen sulfide-containing acidic gas as raw material and includes: A combined reaction section includes a vertical reaction separation device 1, a steam contact section 141, a first gas-liquid contact section 111, a second gas-liquid contact section 121, and a third gas-liquid contact section 131. The steam contact section 141 is located at the bottom of the vertical reaction separation device 1. The first gas-liquid contact section 111 is located above the steam contact section 141, the second gas-liquid contact section 121 is located above the first gas-liquid contact section 111, and the third gas-liquid contact section 131 is located above the second gas-liquid contact section 121, thereby dividing the vertical reaction separation device 1 into a stripping zone 14, a first-stage reaction zone 11, a second-stage reaction zone 12, and a third-stage reaction zone 13. The vertical reaction separation device 1 includes a raw material inlet containing hydrogen sulfide acid gas, which is located at the lower part of the first-stage reaction zone 11. A circulation section includes a primary sodium-containing alkaline solution inlet, a secondary sodium-containing alkaline solution inlet, a tertiary sodium-containing alkaline solution inlet, a secondary circulation pump 31, and a tertiary circulation pump 32. The primary sodium-containing alkaline solution inlet is located at the upper end of the first gas-liquid contact section 111, the secondary sodium-containing alkaline solution inlet is located at the upper end of the second gas-liquid contact section 121, and the tertiary sodium-containing alkaline solution inlet is located at the upper end of the third gas-liquid contact section 131. This pump is used to introduce sodium-containing alkaline solution into a primary reaction zone 11, a secondary reaction zone 12, and a tertiary reaction zone 13, respectively. The inlet of the secondary circulation pump 31 is connected to the outlet of the secondary reaction zone 12, and the outlet of the secondary circulation pump 31 is connected to the primary sodium-containing alkaline solution inlet and the secondary sodium-containing alkaline solution inlet, respectively. The inlet of the tertiary circulation pump 32 is connected to the outlet of the tertiary reaction zone 13, and the outlet of the tertiary circulation pump 32 is connected to the secondary circulating alkaline solution inlet and the tertiary sodium-containing alkaline solution inlet, respectively. The two-stage combined reaction section includes a horizontal gas-liquid reactor 2, a first partition 241, a second partition 242, a second-stage primary gas manifold 212, a second-stage secondary gas manifold 222, a second-stage tertiary gas manifold 232, a second-stage primary ejector 211, a second-stage secondary ejector 221, a second-stage tertiary ejector 231, and a liquid collection manifold 251. The first partition 241 and the second partition 242 divide the horizontal gas-liquid reactor 2 into a two-stage primary reaction zone 21, a two-stage secondary reaction zone 22, and a two-stage tertiary reaction zone 23. The air inlet of the second-stage primary ejector 211 is connected to the top air outlet of the vertical reaction separation device 1, and the discharge outlet of the second-stage primary ejector 211 is connected to the feed inlet of the second-stage primary reaction zone 21. The outlet of the primary reaction zone 21 is connected to the inlet of the secondary primary gas chamber 212. The outlet of the secondary primary gas chamber 212 is connected to the inlet of the secondary ejector 221. The outlet of the secondary ejector 221 is connected to the inlet of the secondary reaction zone 22. The outlet of the secondary reaction zone 22 is connected to the inlet of the secondary gas chamber 222. The outlet of the secondary gas chamber 222 is connected to the inlet of the secondary gas chamber 222. The outlet of the secondary gas chamber 222 is connected to the inlet of the tertiary ejector 231. The outlet of the tertiary ejector 231 is connected to the inlet of the tertiary reaction zone 23. The outlet of the tertiary reaction zone 23 is connected to the inlet of the secondary gas chamber 232. The liquid collection bag 251 is located in the middle of the bottom of the horizontal gas-liquid reactor 2. The second-stage circulation section includes a boundary sodium-containing alkaline solution inlet pipe 8 and a second-stage circulation pump 33. The outlet of the boundary sodium-containing alkaline solution inlet pipe 8 is simultaneously connected to the inlets of the second-stage primary ejector 211, the second-stage secondary ejector 221, and the second-stage tertiary ejector 231. The inlet of the second-stage circulation pump 33 is connected to the outlet of the liquid collection bag 251, and the outlet of the second-stage circulation pump 33 is connected to the inlets of the second-stage primary ejector 211, the second-stage secondary ejector 221, the second-stage tertiary ejector 231, and the inlet of the first-stage tertiary reaction zone 13.

[0029] It should be noted that the sodium-containing alkaline solution introduced into the first-stage sodium-containing alkaline solution inlet, the first-stage second-stage sodium-containing alkaline solution inlet, and the first-stage third-stage sodium-containing alkaline solution inlet can generally be a sodium hydroxide solution.

[0030] It should be noted that the hydrogen sulfide-containing acidic gas entering the vertical reaction device mainly contains hydrogen sulfide. In addition to hydrogen sulfide, the hydrogen sulfide-containing acidic gas also contains impurity components such as water vapor, carbon dioxide, ammonia, and hydrocarbons.

[0031] It should be noted that, in addition to the steam contact section 141, the stripping zone 14 is also equipped with a heating evaporator 142. Through the continuous heating of the heating evaporator 142, the ammonia, oil and other gaseous and / or liquid phase impurities carried in the first-stage effluent alkaline solution are heated and stripped. Some of the water in the first-stage effluent alkaline solution is also heated and vaporized to form oil-containing and / or ammonia-containing gases. These oil-containing and / or ammonia-containing gases flow upward as stripping gases and further strip the impurities carried in the first-stage effluent alkaline solution in the steam contact section 141. These stripped impurities can be discharged at the top of the stripping zone 14.

[0032] It should be noted that the primary reaction zone 11, the secondary reaction zone 12, and the tertiary reaction zone 13 can be isolated by a spacer. The spacer used for isolation can be an elliptical head, a flat cap head, or other types of spacer internals.

[0033] It should be noted that a hydrogen sulfide-containing acidic gas inlet is provided at the lower end of the first gas-liquid contact section 111, which can introduce the hydrogen sulfide-containing acidic gas into the lower part of the first gas-liquid contact section 111; a primary sodium-containing alkaline solution inlet is provided at the upper end of the first gas-liquid contact section 111, which can introduce a primary sodium-containing alkaline solution into the upper part of the first gas-liquid contact section 111 to conduct a countercurrent contact reaction with the introduced hydrogen sulfide-containing acidic gas. Mass transfer, heat transfer and neutralization reactions occur in the countercurrent contact reaction, including the reaction to generate sodium hydrosulfide (NaHS) as shown in formula (1): Na2S(aq) + H2S(aq)→2NaHS(aq) , (1); In the reaction process shown in equation (1), a side reaction that produces sodium sulfide (Na2S) also occurs, namely reaction (2): H2S(aq)+2NaOH(aq)→Na2S(aq)+2H2O, (2); The reactions shown in equations (1) and (2) are both exothermic reactions. When the molar ratio of sodium hydroxide in sodium-containing alkaline solution to hydrogen sulfide in hydrogen sulfide-containing acidic gas is greater than 1.5:1, the reaction shown in equation (2) is dominant. When the molar ratio of sodium hydroxide in sodium-containing alkaline solution to hydrogen sulfide in hydrogen sulfide-containing acidic gas is less than or equal to 1.5:1, the reaction shown in equation (1) is dominant.

[0034] It should be noted that when the acidic gas containing hydrogen sulfide contains carbon dioxide, sodium hydroxide in the sodium-containing alkaline solution will also undergo side reactions with carbon dioxide, including the side reaction to form sodium bicarbonate as shown in formula (3): CO2(aq)+NaOH(aq)→NaHCO3(aq), (3), And including the side reaction that produces sodium carbonate as shown in equation (4): NaHCO3(aq)+NaOH(aq)→Na2CO3(aq)+H2O, (4); The presence of these side reactions not only increases the consumption of sodium-containing alkaline solutions, but also generates a large amount of waste alkaline solutions containing carbonates. Furthermore, these carbonates can contaminate the quality of sodium hydrosulfide products. Therefore, it is crucial to improve the selectivity of hydrogen sulfide absorption and reduce the formation of carbonates. Based on the reaction mechanism that the absorption rate of hydrogen sulfide by sodium-containing alkaline solution is greater than that of carbon dioxide by sodium-containing alkaline solution, this application takes the following measures: ① Reduce the contact time between sodium-containing alkaline solution and hydrogen sulfide-containing acidic gas in the first gas-liquid contact section 111, the second gas-liquid contact section 121 and the third gas-liquid contact section 131 in the first-stage combined reaction section, and in the second-stage first-stage ejector 211, the second-stage second-stage ejector 221 and the second-stage third-stage ejector 231 in the second-stage combined reaction section, thereby reducing the amount of carbon dioxide absorbed by sodium-containing alkaline solution; ② Introduce a first-stage circulation section and a second-stage circulation section to increase the circulation volume of sodium-containing alkaline solution and reduce the pH value of the circulating alkaline solution in the first-stage circulation section and the second-stage circulation section, so as to suppress the side reaction of generating sodium bicarbonate as shown in formula (3) and the side reaction of generating sodium carbonate as shown in formula (4).

[0035] It should be noted that the reaction for generating sodium hydrosulfide, as shown in formula (1), mainly takes place in the first gas-liquid contact section 111.

[0036] It should be noted that the secondary sodium-containing alkali inlet located at the upper end of the second gas-liquid contact section 121 can be used not only to introduce the secondary sodium-containing alkali from the secondary circulation pump 31, but also as an inlet for the secondary circulating alkali from the tertiary circulation pump 32. The secondary sodium-containing alkali and the secondary circulating alkali can share a liquid distributor. The liquid distributor evenly disperses the secondary sodium-containing alkali and the secondary circulating alkali into sodium-containing alkali droplets. These droplets come into countercurrent contact with the first pure gas in the second gas-liquid contact section 121. The sodium-containing alkali droplets can absorb some of the hydrogen sulfide in the first pure gas, forming a secondary discharge alkali solution. This secondary discharge alkali solution then flows downwards to the bottom of the secondary reaction zone 12 for buffering and... The impurities carried by the gas are separated to form a relatively pure secondary effluent alkali solution. The secondary effluent alkali solution can be pressurized by a secondary circulation pump 31 and cooled by a secondary cooler 41. After passing through a diversion pipe, it can form a primary sodium-containing alkali solution and a secondary sodium-containing alkali solution. The primary sodium-containing alkali solution is distributed evenly by a liquid distributor set in the primary reaction zone 11. The evenly distributed primary feed alkali solution then enters the upper end of the first gas-liquid contact section 111. The secondary sodium-containing alkali solution is distributed evenly by a liquid distributor set in the secondary reaction zone 12. It then flows downward from the upper end of the second gas-liquid contact section 121 and comes into countercurrent contact with the first pure gas flowing upward.

[0037] It should be noted that the first-stage sodium-containing alkali inlet located at the upper end of the third gas-liquid contact section 131, in addition to introducing the first-stage sodium-containing alkali from the first-stage third-stage circulating pump 32, can also be used as the inlet for the first-stage third-stage circulating alkali from the second-stage circulating pump 33. The first-stage sodium-containing alkali and the first-stage circulating alkali can share a liquid distributor. The liquid distributor evenly disperses the first-stage sodium-containing alkali and the first-stage circulating alkali into sodium-containing alkali droplets. These sodium-containing alkali droplets react with the second pure gas in the third gas-liquid contact section. In the countercurrent contact section 131, the sodium-containing alkaline liquid droplets can absorb some of the hydrogen sulfide in the second pure gas and form a first-stage tertiary discharge alkaline liquid. Subsequently, the first-stage tertiary discharge alkaline liquid flows from top to bottom to the bottom of the first-stage tertiary reaction zone 13 for buffering and separation of the impurity gas it carries, forming a relatively pure first-stage tertiary discharge alkaline liquid. This first-stage tertiary discharge alkaline liquid can be pressurized by the first-stage tertiary circulation pump 32 and cooled by the first-stage tertiary cooler 42, and then passed through the diversion pipe to form a first-stage tertiary sodium-containing alkaline liquid and a first-stage secondary circulation alkaline liquid.

[0038] It should be noted that the primary alkali solution can overflow through the downcomer 113 to the top of the stripping zone 14. At this time, a liquid distributor can be installed above the stripping zone 14. These liquid distributors can form the primary alkali solution into uniformly dispersed droplets. These primary alkali solution droplets and the stripping gas generated from the stripping zone 14 from bottom to top will have countercurrent contact in the steam contact section 141. Then, they will enter the stripping zone 14 and be continuously heated. Through the heating evaporator 142, the ammonia, oil and other impurities carried by the primary alkali solution droplets will be stripped. The stripped ammonia, oil and other impurities can be discharged separately from the top of the stripping zone 14, or they can be mixed with the third pure gas from the top of the first-stage tertiary reaction zone 13. Subsequently, the third pure gas will enter the second-stage combined reaction section, where the residual hydrogen sulfide will be further removed by the second-stage primary ejector 211.

[0039] It should be noted that if the third purified gas in the first stage combined reaction section does not contain hydrogen sulfide or the content of hydrogen sulfide meets the emission index requirements, it can be discharged directly from the vertical reaction separation device without being treated by the subsequent second stage combined reaction section, or it can be mixed with the purified gas from other areas before being discharged from the device.

[0040] It should be noted that after the primary alkali solution is stripped of impurities such as ammonia and oil in the stripping zone 14, the quality of the primary alkali solution in the stripping zone 14 meets the requirements of GB / T 23937-2020 "Industrial Sodium Hydrosulfide". After being transported to the product cooler 44 through the sodium hydrosulfide pipeline for cooling, it can be used as a sodium hydrosulfide product discharge device.

[0041] It should be noted that the components for mass transfer, heat transfer, and reaction in the steam contact section 141, the first gas-liquid contact section 111, the second gas-liquid contact section 121, and the third gas-liquid contact section 131 are trays and / or packing, respectively. When trays are used in the steam contact section 141, the number of trays is 4 to 8. When packing is used in the steam contact section 141, the first gas-liquid contact section 111, the second gas-liquid contact section 121, and the third gas-liquid contact section 131, the packing can be random packing or structured packing, and the packing height can be 1.5m to 4.5m. Simultaneously, the diameter of the trays and / or packing bed in the steam contact section 141, the first gas-liquid contact section 111, the second gas-liquid contact section 121, and the third gas-liquid contact section 131 is 500 Nm per square meter of cross-sectional area. 3 / h to 3000Nm 3 The design should be based on a capacity of / h for hydrogen sulfide-containing acidic gas; when the CO2 volume fraction in the hydrogen sulfide-containing acidic gas is greater than 5%, the upper limit of the treatment load should be set, such as 2100 Nm³ per square meter of cross-sectional area.3 / h, 2400Nm 3 / h, 2700Nm 3 / h, 3000 Nm 3 The system is designed to generate a hydrogen sulfide-containing acidic gas per hour to shorten the reaction time, suppress side reactions such as sodium carbonate and sodium bicarbonate, and ensure that the mass fraction of such byproducts in the sodium hydrosulfide product is less than 0.5%.

[0042] It should be noted that in a combined reaction section, the mass flow rate of the first-stage sodium-containing alkaline solution is controlled by the bottom liquid level of the second-stage reaction zone 12; the mass flow rate of the second-stage circulating alkaline solution is controlled by the bottom liquid level of the third-stage reaction zone 13; the mass flow rate of the third-stage circulating alkaline solution is controlled by the liquid level of the liquid collection bag 251 of the subsequent horizontal gas-liquid separator; and the discharge mass flow rate of sodium hydrosulfide product is controlled by the bottom liquid level of the stripping zone 14.

[0043] It should be noted that in a combined reaction section, the mass flow rate of the secondary sodium-containing alkaline solution is 0 to 5 times that of the sodium-containing alkaline solution inlet pipe 8. The pH value of the secondary effluent alkaline solution is maintained between 9.0 and 11.0 by adjusting the mass flow rate of the secondary sodium-containing alkaline solution. Similarly, the mass flow rate of the tertiary sodium-containing alkaline solution is 0 to 5 times that of the sodium-containing alkaline solution inlet pipe 8. The pH value of the tertiary effluent alkaline solution is maintained between 9.5 and 11.5 by adjusting the mass flow rate of the tertiary sodium-containing alkaline solution.

[0044] It should be noted that the structures of the second-stage primary injector 211, the second-stage secondary injector 221, and the second-stage tertiary injector 231 are similar. Taking the second-stage primary injector 211 as an example, the second-stage primary injector 211 generally consists of four parts: a nozzle, a receiving chamber, a mixing chamber, and a diffusion chamber. When the sodium-containing alkaline solution in the first boundary region with a certain pressure enters the nozzle and is sprayed through the nozzle, the sodium-containing alkaline solution in the first boundary region will generate a very high flow velocity. The high flow velocity of the sodium-containing alkaline solution in the first boundary region will form a low-pressure zone around the nozzle. These low-pressure zones can guide the third pure gas into the receiving chamber. In the receiving chamber, the sodium-containing alkaline solution in the first boundary region and the third pure gas will be initially mixed, and then enter the mixing chamber to be fully mixed and form turbulence. At the same time, during the formation of turbulence, reactions including the formation of sodium hydrosulfide as shown in formula (1) and the formation of sodium hydrosulfide as shown in formula (2) will occur. (2) shows the side reaction for the formation of sodium sulfide. Among them, the side reaction for the production of sodium sulfide as shown in formula (2) is the main reaction. After the reaction, the sodium-containing alkaline solution in the first boundary zone and the third pure gas enter the diffusion chamber together. At this time, the outlet pressure of the diffusion chamber increases. No additional pressurization equipment is required in this process, which simplifies the overall mixing process. At the same time, the entire process reacts in a very short time range of 0.01s to 0.3s, which is conducive to the selective absorption of hydrogen sulfide in the third pure gas by the sodium-containing alkaline solution in the first boundary zone and reduces the formation of side reaction products such as sodium carbonate and sodium bicarbonate. It should be noted that the secondary effluent alkaline solution in the collection tank 251, after being pressurized by the second-stage circulating pump 33 and cooled by the second-stage cooler 43, is divided into four parts through a diversion pipe: a first-stage tertiary circulating alkaline solution, a second-stage primary circulating alkaline solution, a second-stage secondary circulating alkaline solution, and a second-stage tertiary circulating alkaline solution. Specifically, the first-stage tertiary circulating alkaline solution enters the upper end of the third gas-liquid contact section 131. The second-stage primary circulating liquid, after mixing with the sodium-containing alkaline solution in the first boundary zone, is sent to the second-stage primary ejector 211 to react with hydrogen sulfide in the third pure gas. The second-stage secondary circulating liquid, after mixing with the sodium-containing alkaline solution in the second boundary zone, is sent to the second-stage secondary ejector 221 to react with hydrogen sulfide in the second-stage primary tail gas. The second-stage tertiary circulating liquid, after mixing with the sodium-containing alkaline solution in the third boundary zone, is sent to the second-stage tertiary ejector 231 to react with hydrogen sulfide in the second-stage secondary tail gas.

[0045] It should be noted that the mass flow rate of the first-stage circulating alkaline solution in the second stage is 0 to 5 times the mass flow rate of the sodium-containing alkaline solution introduced through the boundary sodium-containing alkaline solution inlet pipe 8; the mass flow rate of the second-stage circulating alkaline solution in the second stage is 0 to 4 times the mass flow rate of the sodium-containing alkaline solution introduced through the boundary sodium-containing alkaline solution inlet pipe 8; and the mass flow rate of the third-stage circulating alkaline solution in the second stage is 0 to 3 times the mass flow rate of the sodium-containing alkaline solution introduced through the boundary sodium-containing alkaline solution inlet pipe 8. In the sodium-containing alkaline solution introduced through the boundary sodium-containing alkaline solution inlet pipe 8, the mass flow rate of the first boundary sodium-containing alkaline solution is 0.4 to 0.6 times that of the total mass flow rate of the boundary sodium-containing alkaline solution introduced through the boundary sodium-containing alkaline solution inlet pipe 8, the mass flow rate of the second boundary sodium-containing alkaline solution is 0.3 to 0.5 times that of the total mass flow rate of the boundary sodium-containing alkaline solution introduced through the boundary sodium-containing alkaline solution inlet pipe 8, and the mass flow rate of the third boundary sodium-containing alkaline solution is 0.1 to 0.4 times that of the total mass flow rate of the boundary sodium-containing alkaline solution introduced through the boundary sodium-containing alkaline solution inlet pipe 8.

[0046] It should be noted that the first partition 241 and the second partition 242 in the two-stage combined reaction section meet the following design requirements: (1) The outer diameter of the first partition 241 and the second partition 242 is the same as the inner diameter of the horizontal gas-liquid reactor 2, and they are fixed to the inner wall of the horizontal gas-liquid reactor 2 by welding or flange fixing; (2) Taking the bottom of the horizontal gas-liquid reactor 2 as the reference, the height of the top of the slots opened by the first partition 241 and the second partition 242 is 0.1 to 0.3 times the lowest liquid level height of the horizontal gas-liquid reactor 2 under normal operating conditions.

[0047] It should be noted that the sodium-containing alkaline solution introduced by the sodium-containing alkaline solution inlet pipe 8 in this boundary area is an aqueous solution of sodium hydroxide with a mass fraction of 25% to 50%; the working pressure of the sodium-containing alkaline solution inlet pipe 8 in this boundary area is 0.3MPa to 3.5MPa, and the working temperature of the sodium-containing alkaline solution inlet pipe 8 in this boundary area is 30℃ to 50℃.

[0048] In some optional embodiments, a combined reaction section further includes: a downcomer 113, a first gas riser 112, and a second gas riser 122. The downcomer 113 is fixedly connected between the stripping zone 14 and the first-stage reaction zone 11. The first gas riser 112 is fixedly connected between the first-stage reaction zone 11 and the second-stage reaction zone 12. The second gas riser 122 is fixedly connected between the second-stage reaction zone 12 and the third-stage reaction zone 13.

[0049] In these embodiments, the downcomer 113 is used to maintain the bottom liquid level of the first-stage reaction zone 11, providing sufficient buffer time for the first-stage effluent alkali solution, and allowing the first-stage effluent alkali solution to automatically flow from the bottom of the first-stage reaction zone 11 to the upper part of the stripping zone 14 under gravity. In addition, the first riser 112 is used to introduce the first pure gas from the top of the first-stage reaction zone 11 into the second-stage reaction zone 12, while effectively isolating the first-stage effluent alkali solution at the bottom of the second-stage reaction zone 12, preventing the second-stage effluent alkali solution from flowing into the first-stage reaction zone 11. Furthermore, the second riser 122 is used to introduce the second pure gas from the top of the second-stage reaction zone 12 into the third-stage reaction zone 13, and prevent the first-stage effluent alkali solution at the bottom of the third-stage reaction zone 13 from flowing into the second-stage reaction zone 12. Through the channel function of the first riser 112 and the second riser 122, not only can additional contact during gas-liquid transport be isolated, but also the smooth progress of the reaction in different reaction zones can be ensured.

[0050] It should be noted that the stripping zone 14 and the primary reaction zone 11 can be isolated by a separator to prevent cross-contamination of materials between them. This separator can be an elliptical head or a flat cap. The downcomer 113 can be a cylindrical pipe that runs through this separator between the stripping zone 14 and the primary reaction zone 11. A sealing disc is installed at the bottom of the downcomer 113 to effectively prevent the hydrogen sulfide-containing acidic gas from the primary reaction zone 11 from entering the stripping zone 14. Furthermore, a liquid distributor can be installed at the bottom of the downcomer 113; this liquid distributor can be a disc type or a trough type.

[0051] It should be noted that the primary reaction zone 11 and the secondary reaction zone 12, as well as the secondary reaction zone 12 and the tertiary reaction zone 13, are separated by isolation elements to prevent the materials on both sides of the isolation element from flowing together. The isolation element can be an elliptical head or a flat cap head. The first gas riser 112 can be a cylindrical pipe passing through the isolation element between the primary reaction zone 11 and the secondary reaction zone 12; the second gas riser 122 can be a cylindrical pipe passing through the isolation element between the secondary reaction zone 12 and the tertiary reaction zone 13.

[0052] In some alternative embodiments, the vertical distance between the bottom end face of the downcomer 113 and the top end face of the steam contact section 141 is 100 mm to 300 mm; and / or The height difference h1-h2 between the length h1 of the first gas riser pipe 112 located inside the first secondary reaction zone 12 and the highest liquid level h2 inside the first secondary reaction zone 12 is 100mm to 300mm; and / or The height difference h3-h4 between the length h3 of the second gas riser pipe 122 located inside the first stage of the tertiary reaction zone 13 and the highest liquid level h4 inside the first stage of the tertiary reaction zone 13 is 100mm to 300mm.

[0053] In these embodiments, the downcomer 113, with a vertical distance of 100mm to 300mm between its length and the top end face of the steam contact section 141, facilitates the uniform distribution of the primary effluent alkaline solution within the steam contact section 141. Furthermore, the first riser 112, located within the secondary reaction zone 12 with a length h1 and a height difference h1-h2 of 100mm to 300mm between the length h1 and the highest liquid level h2 within the secondary reaction zone 12, allows the primary purified gas to rise smoothly, preventing excessive entrainment of mist. Additionally, the second riser 122, located within the tertiary reaction zone 13 with a length h3 and a height difference h3-h4 of 100mm to 300mm between the length h3 and the highest liquid level h4 within the tertiary reaction zone 13, allows the secondary purified gas to rise smoothly, preventing excessive entrainment of mist.

[0054] The vertical distance between the bottom end face of the downcomer 113 and the top end face of the steam contact section 141 can be 100mm, 150mm, 200mm, 250mm or 300mm. The height difference h1-h2 between the length h1 of the first gas riser pipe 112 located inside the first secondary reaction zone and the highest liquid level h2 inside the first secondary reaction zone 12 can be 100mm, 150mm, 200mm, 250mm or 300mm. The height difference h3-h4 between the length h3 of the second riser pipe 122 located inside a third-stage reaction zone 13 and the highest liquid level h4 inside the third-stage reaction zone 13 can be 100mm, 150mm, 200mm, 250mm or 300mm.

[0055] In some alternative embodiments, a combined reaction section is further provided with a first rainproof cap and a second rainproof cap. The first rainproof cap is fixedly connected above the first air riser 112, and the second rainproof cap is fixedly connected above the second air riser 122. The bottom outer diameter of the first rainproof cap is 1.2 to 1.4 times the outer diameter of the first air riser 112; the bottom outer diameter of the second rainproof cap is 1.15 to 1.35 times the outer diameter of the second air riser 122.

[0056] In these embodiments, a first rain cap is provided above the first riser pipe 112 and a second rain cap is provided above the second riser pipe 122. This prevents the first riser pipe 113 and the second riser pipe 122 from being blocked by liquid, thus avoiding the pressure buildup and escape of hydrogen sulfide-containing acidic gas. In addition, the first rain cap, with a bottom outer diameter of 1.2 to 1.4 times the outer diameter of the first riser pipe 113, allows the first pure gas to diffuse evenly into the first secondary reaction zone 12, ensuring sufficient contact between the first pure gas and the first secondary sodium-containing alkaline solution, which is beneficial to improving the reaction efficiency of the second neutralization reaction. The second rain cap, with a bottom outer diameter of 1.15 to 1.35 times the outer diameter of the second riser pipe 122, allows the second pure gas to diffuse evenly into the first tertiary reaction zone 13, ensuring sufficient contact between the second pure gas and the first tertiary sodium-containing alkaline solution, which is beneficial to improving the reaction efficiency of the third neutralization reaction.

[0057] It should be noted that, in specific implementation, the bottom outer diameter of the first rain cap can be 1.2 times, 1.25 times, 1.3 times, 1.35 times, or 1.4 times the outer diameter of the first air riser 112; the bottom outer diameter of the second rain cap can be selected as 1.2 times, 1.25 times, 1.3 times, 1.35 times, or 1.4 times the outer diameter of the second air riser 122.

[0058] In some alternative embodiments, the cross-sectional area of ​​the first riser 112 is 15% to 35% of the cross-sectional area of ​​the vertical reaction separation device 1; and / or The cross-sectional area of ​​the second gas riser 122 is 15% to 35% of the cross-sectional area of ​​the vertical reaction separation device 1.

[0059] In these embodiments, the first riser pipe 112, with a cross-sectional area of ​​15% to 35% of the cross-sectional area of ​​the vertical reaction separation device 1, ensures the normal rise of the first pure gas and limits its flow rate, preventing the first pure gas from carrying a section of primary sodium-containing alkaline solution into the secondary reaction zone 12; the second riser pipe 122, with a cross-sectional area of ​​15% to 35% of the cross-sectional area of ​​the vertical reaction separation device 1, ensures the normal rise of the second pure gas and limits its flow rate, preventing the second pure gas from carrying a section of secondary sodium-containing alkaline solution into the tertiary reaction zone 13. The cross-sectional area of ​​the first gas riser 112 can be 15%, 16%, 17%, 18%, 19%, 20%, 25%, 30% or 35% of the cross-sectional area of ​​the vertical reaction separation device 1.

[0060] The cross-sectional area of ​​the second gas riser 122 can be 15%, 16%, 17%, 18%, 19%, 20%, 25%, 30% or 35% of the cross-sectional area of ​​the vertical reaction separation device 1.

[0061] In some optional embodiments, a circulation section further includes a secondary cooler 41, a tertiary cooler 42, and a product cooler 44. The secondary cooler 41 is connected in series to the outlet of the secondary circulation pump 31, the tertiary cooler 42 is connected in series to the outlet of the tertiary circulation pump 322, and the product cooler 44 is connected in series to the outlet of the vertical reaction separation device 1.

[0062] In some optional embodiments, a secondary cooler 41 and a tertiary cooler 42 are introduced into a circulation section. The secondary cooler 41 is connected in series to the outlet of the secondary circulation pump 31, and the tertiary cooler is connected in series to the outlet of the tertiary circulation pump 32. These coolers can remove the heat of reaction, maintain the reaction temperature in the primary reaction zone 11, the secondary reaction zone 12, and the tertiary reaction zone 13, and reduce the production of by-products. In addition, a product cooler 44 is provided in the circulation section to reduce the discharge temperature of sodium hydrosulfide product.

[0063] In some alternative embodiments, a first-stage combined reaction section is further provided with a demister 132, which is fixed to the top of the vertical reaction separation device 1 to remove the alkaline solution entrained in the third pure gas, thereby creating favorable conditions for the efficient reaction of hydrogen sulfide and sodium-containing alkaline solution in the subsequent second-stage combined reaction section.

[0064] In some alternative embodiments, the two-stage combined reaction unit further includes a two-stage cooler 43, which is connected in series with the outlet of the two-stage circulating pump 33.

[0065] In these embodiments, the secondary effluent alkali solution at the outlet of the secondary circulation pump 33 can be cooled by the secondary cooler 43 to remove the heat of reaction, which helps to maintain the reaction temperature in the subsequent primary tertiary reaction zone 13, the secondary primary ejector 211, the secondary secondary ejector 221, and the secondary tertiary ejector 231 and reduce the production of by-products.

[0066] In some alternative implementations, the system further includes: The control unit includes a level controller 261, an online hydrogen sulfide analyzer 5, a boundary alkaline solution mass flow regulating valve 6, and a secondary discharge alkaline solution mass flow control valve 7. The level controller 261 is installed inside the horizontal gas-liquid reactor 2 to control the alkaline solution level in the horizontal gas-liquid reactor 2. The online hydrogen sulfide analyzer 5 is installed at the outlet of the second-stage tertiary gas manifold 232. The boundary alkaline solution mass flow regulating valve 6 is installed at the outlet of the boundary sodium-containing alkaline solution inlet pipe 8. The secondary discharge alkaline solution mass flow control valve 7 is installed at the outlet of the second-stage circulating pump 33. The secondary discharge alkaline solution mass flow control valve 7 is connected to the level controller 261 via an electrical signal, and the online hydrogen sulfide analyzer 5 is connected to the boundary alkaline solution mass flow regulating valve 6 via an electrical signal.

[0067] In these embodiments, the concentration of hydrogen sulfide in the exhaust gas is detected in real time by an online hydrogen sulfide analyzer 5, and the opening and closing degree of the boundary alkaline solution mass flow regulating valve 6 is adjusted by an electrical signal to increase the feed rate of fresh boundary sodium-containing alkaline solution and improve the absorption capacity of sodium-containing alkaline solution in different injectors; then, the liquid level controller 261 collects the liquid level of the secondary effluent alkaline solution in the horizontal gas-liquid reactor 2 in real time, and the liquid flow rate of the collection bag 251 is adjusted by the secondary effluent alkaline solution mass flow control valve 7 to ensure the stability of the liquid level of the sodium-containing alkaline solution input by the boundary sodium-containing alkaline solution inlet pipe 8 and the secondary effluent alkaline solution circulating in the collection bag 251.

[0068] It should be noted that the level of the secondary effluent alkali in the horizontal gas-liquid reactor 2 is maintained stably through the coordinated regulation of the level controller 261 and the secondary effluent alkali mass flow control valve 7. Specifically, when the level of the secondary effluent alkali in the horizontal gas-liquid reactor 2 is higher than the normal level, the level controller 261 detects the level signal through its built-in level monitoring instrument and calculates the result using its built-in PLC. If the calculation result is not within the required range, the level controller 261 sends an electrical signal to the secondary effluent alkali mass flow control valve 7 to adjust the opening of the valve. Conversely, when the level of the secondary effluent alkali in the horizontal gas-liquid reactor 2 is lower than the normal level, the level controller 261 adjusts the opening of the secondary effluent alkali mass flow control valve 7 based on the same detection and calculation process to maintain the secondary effluent alkali in the horizontal gas-liquid reactor 2 at the normal level and meet the relevant requirements.

[0069] It should be noted that when the hydrogen sulfide online analyzer 5 detects that the hydrogen sulfide content in the purified exhaust gas is higher than the preset value (for example, the volume fraction of hydrogen sulfide in the purified exhaust gas is ≤0.0007%), the hydrogen sulfide online analyzer 5 outputs and analyzes the hydrogen sulfide content data, determines the opening degree of the boundary alkaline solution mass flow regulating valve 6, adjusts the opening degree of the boundary alkaline solution mass flow regulating valve 6, and adjusts the mass flow rate of the sodium-containing alkaline solution entering the boundary zone in the second-stage primary injector 211, the second-stage secondary injector 221 and the second-stage tertiary injector 231 until the hydrogen sulfide content in the purified exhaust gas reaches the preset value.

[0070] It should be noted that a circulation pipeline can also be installed on the output pipeline of sodium hydrosulfide product in the vertical reaction separation device 1. Under normal operation, the material flow rate output by the circulation pipeline is 0. If the content of impurity components (such as sodium sulfide, sodium carbonate, and sodium bicarbonate) in the sodium hydrosulfide product is high, the circulation pipeline can be opened. At this time, part of the sodium hydrosulfide product returns to the inlet of the second-stage circulation pump 33 through the circulation pipeline and mixes with the secondary discharge alkaline solution. Then, it returns to the upper part of the third gas-liquid contact section 131 of the first-stage combined reaction section and the second-stage first-stage ejector 211 of the second-stage combined reaction section for further processing to reduce the content of impurity components in the final sodium hydrosulfide product.

[0071] It should be noted that if the purified exhaust gas contains ammonia, an ammonia absorption tower can be added for treatment. After the purified exhaust gas is introduced into the ammonia absorption tower, it comes into countercurrent contact with the demineralized water or deoxygenated water entering the tower from top to bottom. Utilizing the highly efficient absorption of ammonia by the water in the demineralized water or deoxygenated water, the ammonia component in the purified exhaust gas can be separated from the purified exhaust gas. The aqueous phase of the demineralized water or deoxygenated water after ammonia absorption gradually forms crude ammonia water. This crude ammonia water can be further transported to an ammonia distillation tower for purification and refining, ultimately obtaining a refined ammonia water product that meets the requirements of HG / T 5353-2018 "Industrial Ammonia Water" standard.

[0072] Figure 3 An exemplary schematic diagram of the distribution hole structure of a two-stage primary distributor in a system for preparing high-purity sodium hydrosulfide is provided. In some optional embodiments, the two-stage combined reaction unit further includes: a second-stage primary distributor 213, a second-stage primary baffle 214, a second-stage secondary distributor 223, a second-stage secondary baffle 224, a second-stage tertiary distributor 233, and a second-stage tertiary baffle 234; the second-stage primary distributor 213 is fixedly connected to the outlet of the second-stage primary injector 211, and the second-stage primary baffle 214 is fixedly connected to the inlet of the second-stage primary air manifold 212, with the outlet end face of the second-stage primary distributor 213 and the vertical face of the second-stage primary baffle 214 maintained at a distance; the second-stage secondary... The first-stage distributor 223 is fixedly connected to the outlet of the second-stage injector 221. The second-stage baffle 224 is located at the inlet of the second-stage air manifold 222, and the outlet end face of the second-stage distributor 223 is spaced apart from the vertical face of the second-stage baffle 224. The second-stage third-stage distributor 233 is located at the outlet of the second-stage injector 231, and the second-stage third-stage baffle 234 is located at the inlet of the second-stage air manifold 232, and the outlet end face of the second-stage distributor 233 is spaced apart from the vertical face of the second-stage baffle 234.

[0073] In these embodiments, the introduction of a second-stage primary distributor 213, a second-stage secondary distributor 223, and a second-stage tertiary distributor 233 into the two-stage combined reaction section, along with corresponding introduction of a second-stage primary baffle 214, a second-stage secondary baffle 224, and a second-stage tertiary baffle 234, allows the material flowing out of each distributor to be guided into the horizontal gas-liquid reactor 2 of the two-stage combined reaction section. This is beneficial for improving the reaction efficiency in the subsequent first-stage tertiary reaction zone 13, the second-stage primary ejector 211, the second-stage secondary ejector 221, and the second-stage tertiary ejector 231, and for reducing the production of by-products.

[0074] It should be noted that, as Figure 3 As shown, the two-stage primary distributor 213 can be a T-shaped tubular distributor. The distribution holes of the two-stage primary distributor 213 are evenly arranged on the T-shaped tubular distributor, and the outer diameter of the distribution holes can be 3mm to 20mm. The total cross-sectional area of ​​the distribution holes is 1 to 5 times the cross-sectional area of ​​the outlet pipe of the two-stage primary injector 211.

[0075] Figure 4 An exemplary schematic diagram of the structure between a two-stage primary distributor and a two-stage primary baffle in a system for preparing high-purity sodium hydrosulfide is provided. In some alternative implementations, such as Figure 4 As shown, the discharge direction of the second-stage primary distributor 213 is at an angle of 30° to 60° to the vertical plane of the second-stage primary baffle 214; and / or The discharge direction of the second-stage distributor 223 is at an angle of 30° to 60° to the vertical plane of the second-stage baffle 224; and / or The discharge direction of the two-stage three-level distributor 233 is at an angle of 30° to 60° to the vertical plane of the two-stage three-level baffle 234; In these embodiments, two-stage primary baffles 214, 224, and 234 with vertical planes at 30° to 60° are set in the discharge direction of the two-stage primary distributor 213, the two-stage secondary distributor 223, and the two-stage tertiary distributor 233. This allows a specific angle to be formed between each distributor and the baffle, which promotes the rapid separation of the gas and liquid phases flowing out of each distributor. This is beneficial to improving the reaction efficiency in the subsequent one-stage tertiary reaction zone 13, the two-stage primary ejector 211, the two-stage secondary ejector 221, and the two-stage tertiary ejector 231, and reducing the production of by-products.

[0076] The discharge direction of the two-stage primary distributor 213 can be at an angle of 30°, 35°, 40°, 45°, 50°, 55° or 60° to the vertical plane of the two-stage primary baffle 214.

[0077] The discharge direction of the two-stage secondary distributor 223 can be at an angle of 30°, 35°, 40°, 45°, 50°, 55° or 60° to the vertical plane of the two-stage secondary baffle 224.

[0078] The discharge direction of the two-stage three-stage distributor 233 can be at an angle of 30°, 35°, 40°, 45°, 50°, 55° or 60° to the vertical plane of the two-stage three-stage baffle 234.

[0079] It should be noted that the second-stage first-stage baffle 214 serves to prevent sloshing, improve gas-liquid separation efficiency, and shorten gas-liquid separation time: the second-stage first-stage effluent alkaline solution sprayed from the second-stage first-stage ejector 211 falls onto the second-stage first-stage baffle 214 at an angle of 30° to 60°. The second-stage first-stage baffle 214 buffers and guides the second-stage first-stage effluent alkaline solution to flow downwards to the bottom of the horizontal gas-liquid reactor 2 for buffering. Then, it flows through the slot of the first partition 241 into the liquid collection bag 251. At the same time, the gas carried by the second-stage first-stage effluent alkaline solution is discharged on the surface of the second-stage first-stage baffle 214. This gas enters the second-stage first-stage gas bag 212 for buffering and separation of the liquid carried by the gas, forming the second-stage first-stage tail gas. This second-stage first-stage tail gas then enters the nozzle of the second-stage second-stage ejector 221.

[0080] Figure 5 An exemplary schematic diagram of a system for preparing high-purity sodium hydrosulfide is provided, showing a two-stage primary baffle, a two-stage secondary baffle, and a two-stage tertiary baffle. It should be noted that, as Figure 5 As shown, the structure of the second-stage primary baffle 214 is taken as an example. This second-stage primary baffle 214 is an arc-shaped plate, the outer diameter of which matches the inner diameter of the horizontal gas-liquid reactor 2. It is fixed to the upper inner wall of the horizontal gas-liquid reactor 2 by welding or flange connection. The lowest point of the second-stage primary baffle 214 is 40mm to 400mm higher than the highest liquid level of the horizontal gas-liquid reactor 2 during normal operation. The second-stage secondary baffle 224 and the second-stage tertiary baffle 234 both adopt the same structural design as the second-stage primary baffle 214 and achieve the same function.

[0081] Figure 2 An exemplary schematic diagram of a first or second partition in a system for preparing high-purity sodium hydrosulfide provided in an embodiment of this application is shown; In some alternative implementations, such as Figure 2 As shown, the bottom of the first partition 241 and the second partition 242 are respectively provided with slots so that the sodium-containing alkaline solution in the second-stage primary reaction zone 21, the second-stage secondary reaction zone 22 and the second-stage tertiary reaction zone 23 can flow through the slots; the opening angle of the slots is 30° to 120°.

[0082] In these embodiments, slots with opening angles of 30° to 120° are provided at the bottom of the first partition 241 and the second partition 242. The slots allow the flow of sodium-containing alkaline solution in the two-stage primary reaction zone 21, the two-stage secondary reaction zone 22, and the two-stage tertiary reaction zone 23, and enable the sodium-containing alkaline solution in each reaction zone to mix and form a uniform secondary discharge alkaline solution. This ensures that the secondary discharge alkaline solution reacts fully with the hydrogen sulfide in the third purified gas, reducing the sodium sulfide content in the sodium hydrosulfide product and reducing the hydrogen sulfide content in the purified tail gas.

[0083] The opening angle of the slot can be 30°, 40°, 50°, 60°, 70°, 80°, 90°, 100°, 110° or 120°.

[0084] It should be noted that in the horizontal gas-liquid reactor 2, the sodium-containing alkaline solution flowing in the slots of the first baffle 241 and the second baffle 242 can act as a liquid seal, which can prevent the cross-flow of gas in the second-stage primary reaction zone 21, the second-stage secondary reaction zone 22 and the second-stage tertiary reaction zone 23.

[0085] In summary, the embodiments of this application provide a system for preparing high-purity sodium hydrosulfide. This system achieves high yield and high purity of sodium hydrosulfide product production, as well as low concentration control of hydrogen sulfide in the purified tail gas, through multi-stage reaction enhancement contact and alkaline solution closed-loop multi-stage circulation synergy. The specific mechanism is as follows: I. Core Logic: Under the premise of a simplified process flow and fewer equipment units, a two-stage staged treatment is adopted to meet the requirements of pre-conversion and post-capture of hydrogen sulfide-containing acidic gas, thereby reducing impurities in sodium hydrosulfide products and hydrogen sulfide content in tail gas from the source. The system converts hydrogen sulfide in acidic gas containing hydrogen sulfide into crude sodium hydrosulfide product through a vertical reaction separation device 1 in a first-stage combined reaction section. Then, combined with the deep absorption of the horizontal gas-liquid reactor 2 in the second-stage combined reaction section, the unreacted hydrogen sulfide in the hydrogen sulfide-containing gas is further captured and absorbed, forming a two-stage stepwise reaction of hydrogen sulfide. This not only ensures the efficiency of sodium hydrosulfide generation but also prevents the escape of hydrogen sulfide gas. At the same time, through the integrated design of two-step reaction of vertical reaction + horizontal gas-liquid reaction + zone separation + multi-stage circulation, the enrichment and generation of impurities in sodium hydrosulfide product are reduced.

[0086] II. Core steps in the production of high-yield, high-purity sodium hydrosulfide products: The main sources of impurities in sodium hydrosulfide products are: unreacted raw alkali (e.g., NaOH), byproducts (e.g., sodium sulfide and sodium carbonate), and dopants (e.g., water vapor and hydrocarbons). This system specifically controls these impurities through the following structure: 1. Single-stage vertical reaction: a multi-stage contact + circulating alkali control process to reduce unreacted raw materials and by-products. The vertical reaction separation device 1 in the combined reaction section can be divided into a stripping zone 14 (bottom of the vertical reaction separation device 1), a primary reaction zone 11, a secondary reaction zone 12, and a tertiary reaction zone 13, based on the steam contact section 141, the first gas-liquid contact section 111, the second gas-liquid contact section 121, and the third gas-liquid contact section 131. Then, through a circulation section consisting of a primary sodium-containing alkali inlet, a secondary sodium-containing alkali inlet, a tertiary sodium-containing alkali inlet, a secondary circulation pump 31, and a tertiary circulation pump 32, the stratified feeding of different reaction zones and the circulation of sodium-containing alkali in different reaction zones are realized, achieving precise reaction between hydrogen sulfide and sodium-containing alkali, and reducing impurities in the sodium hydrosulfide product. (1) Multi-stage gas-liquid contact reduces reaction time: Sodium-containing alkaline solution is fed into the corresponding alkaline solution inlets of the first-stage reaction zone 11, the second-stage reaction zone 12, and the third-stage reaction zone 13 respectively, while hydrogen sulfide-containing acidic gas flows upward from the bottom of the first gas-liquid contact section 111, forming countercurrent contact and segmented reaction with the incoming alkaline solution. This design can reduce the reaction time of sodium-containing alkaline solution and hydrogen sulfide-containing acidic gas, and reduce the generation of by-reaction products such as sodium carbonate and sodium bicarbonate. (2) Forming a gradient cycle to increase the yield of sodium hydrosulfide: A secondary circulation pump 31 returns the secondary effluent alkaline solution from the secondary reaction zone 12 to the primary reaction zone 11 or the secondary reaction zone 12. Simultaneously, a tertiary circulation pump 32 returns the tertiary effluent alkaline solution from the tertiary reaction zone 13 to the secondary reaction zone 12 or the tertiary reaction zone 13, forming a gradient circulation where the lower effluent alkaline solution returns to the upper reaction zone. This allows the sodium hydroxide and / or sodium sulfide in the lower effluent alkaline solution to further react with hydrogen sulfide, reducing the amount of fresh sodium-containing alkaline solution used. Specifically, the secondary reaction of the circulating effluent alkaline solution can further consume unreacted hydrogen sulfide in the hydrogen sulfide-containing acidic gas, reducing the sodium hydroxide and / or sodium sulfide content in sodium hydrosulfide, increasing the sodium hydrosulfide yield, and reducing the amount of fresh sodium-containing alkaline solution used in the boundary zone. (3) Steam stripping and separation of steam contact section 141 to remove dopants: the steam contact section 141 of the combined reaction section allows the primary discharge alkaline solution to be stripped by steam, separating the dopants in the primary discharge alkaline solution from the sodium hydrosulfide product. (4) Cooling and temperature control to reduce byproducts: A first-stage circulation section can be equipped with a first-stage secondary cooler 41 and a first-stage tertiary cooler 42: the heat of reaction is removed by cooling and the temperature of the first-stage sodium-containing alkaline solution, the first-stage secondary sodium-containing alkaline solution, the first-stage tertiary sodium-containing alkaline solution and the first-stage secondary circulating alkaline solution is kept stable, so as to avoid the reaction of these sodium-containing alkaline solutions and circulating alkaline solutions with hydrogen sulfide at excessively high temperatures, and at the same time, to prevent the alkaline solution from reacting with carbon dioxide to generate too much sodium carbonate and sodium bicarbonate.

[0087] 2. Two-stage closed-loop circulation: multi-stage rapid reaction + efficient gas-liquid separation to further improve the yield of sodium hydrosulfide and reduce the hydrogen sulfide content in the purified exhaust gas: The bottom collection bag 251 of the horizontal gas-liquid reactor 2 in the two-stage combined reaction section can collect the alkaline solution discharged after the reaction of each stage of the ejector in the two stages. This alkaline solution can be sent back to the first-stage ejector 211, the second-stage ejector 221, and the third-stage ejector 231 in the two-stage circulation section via the second-stage circulation pump 33 to continue absorbing hydrogen sulfide from the pure gas discharged from the first-stage combined reaction section. Alternatively, it can be selectively sent back to the third-stage reaction zone 13 as supplementary third-stage circulating alkaline solution. This closed-loop design of the two-stage combined reaction section has the following characteristics: (1) The combined function of distributor and baffle: The two-stage primary distributor 213, the two-stage secondary distributor 223, and the two-stage tertiary distributor 233 are T-shaped tubular distributors, and these distributors are respectively provided with distribution holes at an angle of 30° to 60° to the vertical plane of the two-stage primary baffle 214, the two-stage secondary baffle 224, and the two-stage tertiary baffle 234. The gas and liquid mixture in these distributors is sprayed onto the corresponding baffles through these inclined distribution holes to achieve gas-liquid separation. The two-stage primary baffle 214, the two-stage secondary baffle 224, and the two-stage tertiary baffle 234 serve as anti-impact baffles and improve gas-liquid separation efficiency and shorten gas-liquid separation time. The liquid separated from these baffle surfaces flows downwards to the bottom of the horizontal gas-liquid separator as the second-stage primary alkali solution, the second-stage secondary alkali solution, and the second-stage tertiary alkali solution, respectively, for buffering. It also separates the carried gas and then flows to the liquid collection bag 251. The separated gas enters the second-stage primary gas bag 212, the second-stage secondary gas bag 222, and the second-stage tertiary gas bag 232, respectively, to further separate the carried liquid. Then, it is used as the second-stage primary tail gas, the second-stage secondary tail gas, and the purified tail gas for further treatment. This combined process has the characteristics of high gas and liquid separation efficiency and simple process and flow. (2) Enhanced gas-liquid mixing by ejectors: short reaction time, few by-products, and high hydrogen sulfide removal efficiency in acidic gases containing hydrogen sulfide. The two-stage combined reaction section serves as a deep absorption section. For the third pure gas discharged from the top of the one-stage combined reaction section, hydrogen sulfide in the third pure gas is almost completely removed by three-stage injection. Specifically, the two-stage first-stage ejector 211, the two-stage second-stage ejector 221, and the two-stage third-stage ejector 231 can atomize the sodium-containing alkaline solution input into the sodium-containing alkaline solution inlet pipe 8 and the secondary discharge alkaline solution circulated from the liquid collection bag 251 into tiny droplets, which fully contact the incoming third pure gas and complete the reaction in a very short time. It has the advantages of few by-products and high hydrogen sulfide removal efficiency. (3) The unique partition structure realizes "one device with three zones", reducing equipment investment and operating costs: The first partition 241 and the second partition 242 in the horizontal gas-liquid reactor 2 are provided with inverted "V" shaped slots. The slots and the first partition 241 and the second partition 242 realize the effect of gas phase isolation and liquid phase connection: The gas phase space of the two-stage primary reaction zone 21, the two-stage secondary reaction zone 22 and the two-stage tertiary reaction zone 23 are effectively separated from the bottom liquid level by the first partition 241 and the second partition 242, preventing gas short circuit in each reaction zone; while the liquid at the bottom of the horizontal gas-liquid reactor 2 can be interconnected and flow through the slots provided by the first partition 241 and the second partition 242. This structure integrates three independent reactors that may need to be connected in series in the traditional process into a single device, which fundamentally simplifies the process flow and pipeline connection, and significantly reduces equipment investment, installation and maintenance costs.

[0088] 2. Control Unit: Real-time monitoring + dynamic adjustment for deep removal of hydrogen sulfide from acidic gases containing hydrogen sulfide. The control unit uses a dual-parameter linkage regulation of liquid level and concentration to ensure that the absorption of hydrogen sulfide in the third purified gas in the two-stage combined reaction section is always at its optimal state. (1) Closed-loop control of alkali distribution by hydrogen sulfide online analyzer 5: The hydrogen sulfide online analyzer 5 is installed at the outlet of the second-stage three-stage gas manifold 232 (the last monitoring point before tail gas emission) to detect the concentration of hydrogen sulfide in the tail gas in real time. If the concentration of hydrogen sulfide in the tail gas exceeds the standard, the opening degree of the boundary alkali mass flow regulating valve 6 is adjusted by means of electric signal, pneumatic signal or electric signal combined with pneumatic signal to increase the feed amount of fresh sodium-containing alkali solution, so as to achieve deep absorption of hydrogen sulfide in the acidic gas containing hydrogen sulfide; (2) The liquid output of the liquid collection bag 251 can be adjusted by the secondary discharge alkaline liquid mass flow control valve 7 to ensure the stability of the liquid level in the horizontal gas-liquid reactor 2.

[0089] In summary, the system for preparing high-purity sodium hydrosulfide provided in this application integrates product purity control and exhaust gas environmental protection control strategies into the same vertical reaction separation device 1. Combined with the circulation system of the first-stage circulation section, the generation of impurities is controlled through the main reaction in the steam contact section 141, the first gas-liquid contact section 111, the second gas-liquid contact section 121, and the third gas-liquid contact section 131. Then, the horizontal gas-liquid reactor 2 of the second-stage combined reaction section deeply absorbs and removes hydrogen sulfide from the third pure gas. In conjunction with the recycling of sodium-containing alkaline solution introduced by the boundary sodium-containing alkaline solution inlet pipe 8 of the second-stage circulation section, the external impurities of the sodium-containing alkaline solution are reduced. This precisely controls and prevents the reaction imbalance between the sodium-containing alkaline solution introduced by the boundary sodium-containing alkaline solution inlet pipe 8 and the acidic gas discharged from the first-stage combined reaction section. Ultimately, the preparation of high-purity sodium hydrosulfide and the purification of exhaust gas with low hydrogen sulfide concentration are achieved simultaneously, without the need for additional impurity removal reagents or exhaust gas treatment agents, which conforms to the design concept of green chemical engineering.

[0090] It should be noted that this single-stage combined reaction unit can be operated individually, or two to six single-stage combined reaction units can be operated in parallel, for example, two, four, or six single-stage combined reaction units can be connected in parallel; alternatively, two to four single-stage combined reaction units can be operated in series, for example, two, three, or four single-stage combined reaction units can be connected in series. Furthermore, the vertical reaction separation device 1 in this single-stage combined reaction unit can be further divided into an N-stage reaction zone, where N can be 3, 4, or 5. Series connection refers to connecting two or more functional units sequentially through a closed pipeline.

[0091] It should be noted that the two-stage combined reaction unit can be operated individually, or two to six two-stage combined reaction units can be operated in parallel, for example, two, four, or six two-stage combined reaction units can be connected in parallel; it can also be operated in series, for example, two, three, or four one-stage combined reaction units can be connected in series. In addition, the vertical reaction separation device 1 in the two-stage combined reaction unit can be divided into two M-stage reaction zones, where M can be 3, 4, or 5.

[0092] Figure 6 An exemplary schematic diagram of a method for preparing high-purity sodium hydrosulfide according to an embodiment of this application is shown; Based on a general inventive concept, such as Figure 6 As shown in the embodiments of this application, a method for preparing high-purity sodium hydrosulfide is provided, the method being adapted to a system, and the method includes: S1. A first-stage sodium-containing alkaline solution is subjected to a first neutralization reaction with the hydrogen sulfide-containing acidic gas to obtain a first-stage pure gas and a first-stage discharge alkaline solution. S2. The first-stage secondary sodium-containing alkaline solution is subjected to a second neutralization reaction with the first pure gas to obtain the second pure gas and the first-stage secondary effluent alkaline solution; wherein, a portion of the first-stage secondary effluent alkaline solution is returned to the first neutralization reaction and recycled as the first-stage primary sodium-containing alkaline solution; S3. The first-stage sodium-containing alkaline solution is subjected to a third neutralization reaction with the second-stage pure gas to obtain the third-stage pure gas and the first-stage third-stage effluent alkaline solution; wherein, a portion of the first-stage third-stage effluent alkaline solution is returned to the second neutralization reaction and recycled as the first-stage second-stage sodium-containing alkaline solution. S4. Mix the first stage of primary discharge alkaline solution, all the remaining first stage of secondary discharge alkaline solution, and all the remaining first stage of tertiary discharge alkaline solution to obtain the primary discharge alkaline solution. S5. Strip the primary effluent alkaline solution to obtain sodium hydrosulfide solution; S6. The sodium-containing alkaline solution and the third purified gas in the boundary area are subjected to two-stage multi-stage injection to obtain secondary discharge alkaline solution and purified tail gas.

[0093] This method is based on the system described above. The specific structure of the system can be referred to in the above embodiments. Since this method adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.

[0094] In some optional embodiments, the temperature of the first neutralization reaction, the second neutralization reaction, and the third neutralization reaction is all between 50°C and 75°C, the pressure of the first neutralization reaction, the second neutralization reaction, and the third neutralization reaction is greater than or equal to 0.10 MPa, and the time of the first neutralization reaction, the second neutralization reaction, and the third neutralization reaction is between 0.5 s and 90 s.

[0095] In these embodiments, the first, second, and third neutralization reactions, with temperatures ranging from 50°C to 75°C, pressures greater than or equal to 0.10 MPa, and reaction times ranging from 0.5 s to 90 s, allow a primary sodium-containing alkaline solution, a secondary sodium-containing alkaline solution, and a tertiary sodium-containing alkaline solution to react fully with hydrogen sulfide-containing acidic gas, the first pure gas, and the second purified gas, respectively, to form a secondary discharge alkaline solution.

[0096] The temperatures for the first, second, and third neutralization reactions can all be 50°C, 55°C, 60°C, 65°C, 70°C, or 75°C.

[0097] In some alternative implementations, the stripping temperature is 110°C to 185°C, and the stripping pressure is greater than or equal to 0.10 MPa.

[0098] In these embodiments, stripping at a temperature of 110°C to 185°C and a pressure of ≥0.10 MPa can fully remove impurities from the primary effluent alkaline solution, yielding a pure sodium hydrosulfide solution.

[0099] The stripping temperature can be 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, 155℃, 160℃, 165℃, 170℃, 175℃, 180℃, or 185℃.

[0100] Figure 7 A detailed flowchart illustrating a method for preparing high-purity sodium hydrosulfide according to an embodiment of this application is shown as an example. In some alternative implementations, such as Figure 7 As shown, the sodium-containing alkaline solution and the third purified gas in the boundary area are subjected to a two-stage multi-stage injection to obtain a secondary effluent alkaline solution and purified tail gas, including the following steps: S601. Divide the sodium-containing alkaline solution in the boundary area into a first boundary area sodium-containing alkaline solution, a second boundary area sodium-containing alkaline solution and a third boundary area sodium-containing alkaline solution. S602. The sodium-containing alkaline solution in the first boundary zone and the third pure gas are subjected to a two-stage first-stage injection to obtain a two-stage first-stage discharge alkaline solution and a two-stage first-stage tail gas. S603. The sodium-containing alkaline solution in the second boundary zone and the tail gas of the second stage are subjected to a second-stage two-stage injection to obtain the second-stage two-stage discharge alkaline solution and the second-stage two-stage tail gas. S604. The sodium-containing alkaline solution in the third boundary zone and the second-stage tail gas are subjected to a second-stage tertiary injection to obtain a second-stage tertiary discharge alkaline solution and purified tail gas. S605. The second-stage primary effluent alkaline solution, the second-stage secondary effluent alkaline solution, and the second-stage tertiary effluent alkaline solution are mixed to obtain a secondary effluent alkaline solution; wherein, a portion of the secondary effluent alkaline solution is returned to the second-stage primary spraying, second-stage secondary spraying, or second-stage tertiary spraying steps and recycled as the boundary sodium-containing alkaline solution. S606. All remaining secondary effluent alkaline solution is returned to the third neutralization reaction and recycled as a tertiary sodium-containing alkaline solution.

[0101] In these embodiments, the sodium-containing alkaline solution in the boundary zone is divided into a first boundary zone sodium-containing alkaline solution, a second boundary zone sodium-containing alkaline solution, and a third boundary zone sodium-containing alkaline solution. These boundary zone sodium-containing alkaline solutions are then injected in two stages with the third pure gas to obtain pure purified exhaust gas.

[0102] In some optional embodiments, the temperatures of the two-stage primary injection, the two-stage secondary injection, and the two-stage tertiary injection are 50°C to 75°C, the pressures of the two-stage primary injection, the two-stage secondary injection, and the two-stage tertiary injection are 0.3MPa to 3.5MPa, and the reaction times of the two-stage primary injection, the two-stage secondary injection, and the two-stage tertiary injection are 0.01s to 0.3s, respectively.

[0103] In these embodiments, the two-stage first-stage injection, the two-stage second-stage injection, and the two-stage third-stage injection at temperatures of 50°C to 75°C, pressures of 0.3MPa to 3.5MPa, and reaction times of 0.01s to 0.3s can promote the full reaction of hydrogen sulfide in the third purified gas and the sodium-containing alkaline solution in the boundary zone, including the sodium-containing alkaline solution in the first boundary zone, the sodium-containing alkaline solution in the second boundary zone, and the sodium-containing alkaline solution in the third boundary zone, to form a pure purified exhaust gas.

[0104] The temperatures for the two-stage primary injection, the two-stage secondary injection, and the two-stage tertiary injection can be 50℃, 55℃, 60℃, 65℃, 70℃, or 75℃, respectively.

[0105] The pressures of the two-stage primary injection, the two-stage secondary injection, and the two-stage tertiary injection can be 0.3 MPa, 0.5 MPa, 1.0 MPa, 2.0 MPa, 2.5 MPa, 3.0 MPa, or 3.5 MPa, respectively.

[0106] The reaction times for the two-stage primary injection, the two-stage secondary injection, and the two-stage tertiary injection can be 0.01s, 0.02s, 0.03s, 0.04s, 0.05s, 0.10s, 0.15s, 0.20s, 0.25s, or 0.30s, respectively.

[0107] In some optional embodiments, the mass flow rate of the sodium-containing alkaline solution in the first boundary region is 0.4 to 0.6 times the mass flow rate of the sodium-containing alkaline solution in the boundary region; and / or The mass flow rate of the sodium-containing alkaline solution in the second boundary zone is 0.3 to 0.5 times that of the mass flow rate of the sodium-containing alkaline solution in the boundary zone; and / or The mass flow rate of sodium-containing alkaline solution in the third boundary zone is 0.1 to 0.4 times that of the mass flow rate of sodium-containing alkaline solution in the boundary zone.

[0108] In these embodiments, the first boundary sodium-containing alkaline solution (0.4 to 0.6 times), the second boundary sodium-containing alkaline solution (0.3 to 0.5 times), and the third boundary sodium-containing alkaline solution (0.1 to 0.4 times) which are different multiples of the mass flow rate of the boundary sodium-containing alkaline solution, can split the boundary sodium-containing alkaline solution into different sodium-containing alkaline solutions, which is conducive to the full reaction of the boundary sodium-containing alkaline solution with hydrogen sulfide in the third purified gas to form pure purified tail gas.

[0109] The mass flow rate of the sodium-containing alkaline solution in the first boundary zone can be 0.4 times, 0.45 times, 0.55 times, or 0.60 times the mass flow rate of the sodium-containing alkaline solution in the boundary zone.

[0110] The mass flow rate of the sodium-containing alkaline solution in the second boundary zone can be 0.3 times, 0.35 times, 0.40 times, 0.45 times, or 0.50 times the mass flow rate of the sodium-containing alkaline solution in the boundary zone.

[0111] The mass flow rate of the sodium-containing alkaline solution in the third boundary zone can be 0.1 times, 0.15 times, 0.20 times, 0.25 times, 0.30 times, 0.35 times, or 0.40 times the mass flow rate of the sodium-containing alkaline solution in the boundary zone.

[0112] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national / industry standards; if there is no corresponding national / industry standard, they are performed according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0113] Example 1 A system for preparing high-purity sodium hydrosulfide, the system using hydrogen sulfide-containing acidic gas as raw material, comprising: A combined reaction section includes a vertical reaction separation device 1, a steam contact section 141, a first gas-liquid contact section 111, a second gas-liquid contact section 121, and a third gas-liquid contact section 131. The steam contact section 141 is located at the bottom of the vertical reaction separation device 1. The first gas-liquid contact section 111 is located above the steam contact section 141, the second gas-liquid contact section 121 is located above the first gas-liquid contact section 111, and the third gas-liquid contact section 131 is located above the second gas-liquid contact section 121, thereby dividing the internal space of the vertical reaction separation device 1 into a stripping zone 14, a first-stage reaction zone 11, a second-stage reaction zone 12, and a third-stage reaction zone 13. The vertical reaction separation device 1 includes a hydrogen sulfide-containing acid gas inlet for conveying hydrogen sulfide-containing acid gas, which is located on the lower side wall of the first-stage reaction zone 11. A circulation section includes a primary sodium-containing alkaline solution inlet, a secondary sodium-containing alkaline solution inlet, a tertiary sodium-containing alkaline solution inlet, a secondary circulation pump 31, and a tertiary circulation pump 32. The primary sodium-containing alkaline solution inlet is located at the upper end of the first gas-liquid contact section 111, the secondary sodium-containing alkaline solution inlet is located at the upper end of the second gas-liquid contact section 121, and the tertiary sodium-containing alkaline solution inlet is located at the upper end of the third gas-liquid contact section 131. The primary sodium-containing alkaline solution inlet, the secondary sodium-containing alkaline solution inlet, and the secondary sodium-containing alkaline solution inlet... The three-stage sodium-containing alkaline solution inlet is used to introduce sodium-containing alkaline solution into the first-stage reaction zone 11, the first-stage second-stage reaction zone 12, and the first-stage tertiary reaction zone 13, respectively; the inlet of the first-stage second-stage circulation pump 31 is connected to the outlet of the first-stage second-stage reaction zone 12, the first-stage sodium-containing alkaline solution inlet, and the first-stage second-stage sodium-containing alkaline solution inlet, respectively; the inlet of the first-stage tertiary circulation pump 32 is connected to the outlet of the first-stage tertiary reaction zone 13, and the outlet of the first-stage tertiary circulation pump 32 is connected to the first-stage second-stage circulating alkaline solution inlet and the first-stage tertiary sodium-containing alkaline solution inlet, respectively; The two-stage combined reaction section includes a horizontal gas-liquid reactor 2, a first partition 241, a second partition 242, a second-stage primary gas manifold 212, a second-stage secondary gas manifold 222, a second-stage tertiary gas manifold 232, a second-stage primary ejector 211, a second-stage secondary ejector 221, a second-stage tertiary ejector 231, and a liquid collection manifold 251. The first partition 241 and the second partition 242 divide the horizontal gas-liquid reactor 2 into a two-stage primary reaction zone 21, a two-stage secondary reaction zone 22, and a two-stage tertiary reaction zone 23. The air inlet of the second-stage primary ejector 211 is connected to the top air outlet of the vertical reaction separation device 1, and the discharge outlet of the second-stage primary ejector 211 is connected to the feed inlet of the second-stage primary reaction zone 21. The outlet of the primary reaction zone 21 is connected to the inlet of the secondary primary gas chamber 212. The outlet of the secondary primary gas chamber 212 is connected to the inlet of the secondary ejector 221. The outlet of the secondary ejector 221 is connected to the inlet of the secondary reaction zone 22. The outlet of the secondary reaction zone 22 is connected to the inlet of the secondary gas chamber 222. The outlet of the secondary gas chamber 222 is connected to the inlet of the secondary gas chamber 222. The outlet of the secondary gas chamber 222 is connected to the inlet of the tertiary ejector 231. The outlet of the tertiary ejector 231 is connected to the inlet of the tertiary reaction zone 23. The outlet of the tertiary reaction zone 23 is connected to the inlet of the secondary gas chamber 232. The liquid collection bag 251 is located in the middle of the bottom of the horizontal gas-liquid reactor 2. The second-stage circulation section includes a boundary sodium-containing alkaline solution inlet pipe 8 and a second-stage circulation pump 33. The outlet of the boundary sodium-containing alkaline solution inlet pipe 8 is simultaneously connected to the inlets of the second-stage primary ejector 211, the second-stage secondary ejector 221, and the second-stage tertiary ejector 231. The inlet of the second-stage circulation pump 33 is connected to the outlet of the liquid collection bag 251, and the outlet of the second-stage circulation pump 33 is connected to the inlets of the second-stage primary ejector 211, the second-stage secondary ejector 221, the second-stage tertiary ejector 231, and the inlet of the first-stage tertiary reaction zone 13.

[0114] The combined reaction section also includes: a downcomer 113, a first gas riser 112, and a second gas riser 122. The downcomer 113 is fixedly connected between the stripping zone 14 and the first-stage reaction zone 11. The first gas riser 112 is fixedly connected between the first-stage reaction zone 11 and the second-stage reaction zone 12. The second gas riser 122 is fixedly connected between the second-stage reaction zone 12 and the third-stage reaction zone 13.

[0115] The vertical distance between the bottom end face of the downcomer 113 and the top end face of the steam contact section 141 is 200 mm; The height difference h1-h2 between the length h1 of the first gas riser pipe 112 located inside the first secondary reaction zone 12 and the highest liquid level h2 inside the first secondary reaction zone 12 is 150mm. The height difference h3-h4 between the length h3 of the second gas riser pipe 122 located inside the first stage of the tertiary reaction zone 13 and the highest liquid level h4 inside the first stage of the tertiary reaction zone 13 is 150mm.

[0116] The combined reaction section also includes: a first rainproof cap and a second rainproof cap. The first rainproof cap is fixedly connected to the top of the first air riser 112, and the second rainproof cap is fixedly connected to the top of the second air riser 122. The bottom outer diameter of the first rainproof cap is 1.25 times the outer diameter of the first air riser 112, and the bottom outer diameter of the second rainproof cap is 1.20 times the outer diameter of the second air riser 122.

[0117] The cross-sectional area of ​​the first gas riser 112 is 25% of the cross-sectional area of ​​the vertical reaction separation device 1; The cross-sectional area of ​​the second gas riser 122 is 25% of the cross-sectional area of ​​the vertical reaction separation device 1.

[0118] The circulation section also includes a secondary cooler 41, a tertiary cooler 42, and a product cooler 44. The secondary cooler 41 is connected in series to the outlet of the secondary circulation pump 31, the tertiary cooler 44 is connected in series to the outlet of the tertiary circulation pump 32, and the product cooler 44 is connected in series to the outlet of the vertical reaction separation device 1.

[0119] The combined reaction section also includes a demister 132, which is fixedly connected to the top of the vertical reaction separation device 1.

[0120] The two-stage combined reaction section also includes a two-stage cooler 43, which is connected in series to the discharge port of the two-stage circulating pump 33.

[0121] The system also includes: The control unit includes a level controller 261, an online hydrogen sulfide analyzer 5, a boundary alkaline solution mass flow regulating valve 6, and a secondary discharge alkaline solution mass flow control valve 7. The level controller 261 is installed inside the horizontal gas-liquid reactor 2 to control the alkaline solution level in the horizontal gas-liquid reactor 2. The online hydrogen sulfide analyzer 5 is installed at the outlet of the second-stage tertiary gas manifold 232. The boundary alkaline solution mass flow regulating valve 6 is installed at the outlet of the boundary sodium-containing alkaline solution inlet pipe 8. The secondary discharge alkaline solution mass flow control valve 7 is installed at the outlet of the second-stage circulating pump 33. The secondary discharge alkaline solution mass flow control valve 7 is connected to the level controller 261 via an electric signal and / or a pneumatic signal. The online hydrogen sulfide analyzer 5 is connected to the boundary alkaline solution mass flow regulating valve 6 via an electric signal and / or a pneumatic signal.

[0122] The two-stage combined reaction unit also includes: a second-stage primary distributor 213, a second-stage primary baffle 214, a second-stage secondary distributor 223, a second-stage secondary baffle 224, a second-stage tertiary distributor 233, and a second-stage tertiary baffle 234; the second-stage primary distributor 213 is fixedly connected to the outlet end of the second-stage primary injector 211, and the second-stage primary baffle 214 is fixedly connected to the inlet end of the second-stage primary air manifold 212, with a 200mm gap between the outlet end face of the second-stage primary distributor 213 and the vertical face of the second-stage primary baffle 214; the second-stage secondary distributor 223 is fixedly connected to... The discharge port of the second-stage secondary injector 221 is fixedly connected to the air inlet end of the second-stage secondary air manifold 222, and the discharge port end face of the second-stage secondary distributor 223 is set at a 200mm interval with the vertical surface of the second-stage secondary baffle 224; the second-stage tertiary distributor 233 is fixedly connected to the discharge port end of the second-stage tertiary injector 231, and the second-stage tertiary baffle 234 is fixedly connected to the air inlet end of the second-stage tertiary air manifold 232, and the discharge port end face of the second-stage tertiary distributor 233 is set at a 200mm interval with the vertical surface of the second-stage tertiary baffle 234.

[0123] The discharge direction of the second-stage primary distributor 213 is at an angle of 30° to 60° to the vertical plane of the second-stage primary baffle 214; and / or The discharge direction of the second-stage distributor 223 is at an angle of 30° to 60° to the vertical plane of the second-stage baffle 224; and / or The discharge direction of the second-stage distributor 223 is at an angle of 30° to 60° to the vertical plane of the second-stage baffle 224.

[0124] The bottom of the first partition 241 and the second partition 242 are respectively provided with slots so that the sodium-containing alkaline solution in the two-stage primary reaction zone 21, the two-stage secondary reaction zone 22 and the two-stage tertiary reaction zone 23 can flow through the slots; the opening angle of the slots is 30° to 120°.

[0125] The temperature was 85℃, the pressure was 0.650MPa, and the mass flow rate was 3706.35Nm³. 3 Sodium hydrosulfide is produced using a certain hydrogen sulfide-containing acidic gas with a flow rate of 165.462 kmol / h as raw material. The composition of this hydrogen sulfide-containing acidic gas, by volume fraction, is: hydrogen: 0.06%, water: 28.46%, hydrogen sulfide: 19.52%, ammonia: 48.82%, carbon dioxide: 2.70%, methane: 0.27%, ethane: 0.05%, propane: 0.02%, and butane: 0.10%.

[0126] The sodium-containing alkaline solution introduced by the boundary sodium-containing alkaline solution inlet pipe 8 is a sodium hydroxide aqueous solution with a mass fraction of 40% and a temperature of 40℃. The pressure of the sodium-containing alkaline solution introduced into the second-stage combined reaction section through the boundary sodium-containing alkaline solution inlet pipe 8 is 1.0 MPa, and the mass flow rate of the sodium-containing alkaline solution is 3319.31 kg / h.

[0127] Figure 7 As shown in the embodiments of this application, a method for preparing high-purity sodium hydrosulfide is provided, the method being adapted to a system, and the method includes: S1. A first-stage sodium-containing alkaline solution is subjected to a first neutralization reaction with the hydrogen sulfide-containing acidic gas to obtain a first-stage pure gas and a first-stage discharge alkaline solution. S2. The first-stage secondary sodium-containing alkaline solution is subjected to a second neutralization reaction with the first pure gas to obtain the second pure gas and the first-stage secondary effluent alkaline solution; wherein, a portion of the first-stage secondary effluent alkaline solution is returned to the first neutralization reaction and recycled as the first-stage primary sodium-containing alkaline solution; S3. The sodium-containing alkaline solution from the first stage is subjected to a third neutralization reaction with the second pure gas to obtain the third pure gas and the first stage tertiary effluent alkaline solution; wherein, a portion of the first stage tertiary effluent alkaline solution is returned to the second neutralization reaction and recycled as the first stage secondary circulating alkaline solution; S4. Mix the first stage of primary discharge alkaline solution, all the remaining first stage of secondary discharge alkaline solution, and all the remaining first stage of tertiary discharge alkaline solution to obtain the primary discharge alkaline solution. S5. Strip the primary effluent alkaline solution to obtain sodium hydrosulfide solution; S601. Divide the sodium-containing alkaline solution in the boundary area into a first boundary area sodium-containing alkaline solution, a second boundary area sodium-containing alkaline solution and a third boundary area sodium-containing alkaline solution. S602. The sodium-containing alkaline solution in the first boundary zone and the third pure gas are subjected to a two-stage first-stage injection to obtain a two-stage first-stage discharge alkaline solution and a two-stage first-stage tail gas. S603. The sodium-containing alkaline solution in the second boundary zone and the tail gas of the second stage are subjected to a second-stage two-stage injection to obtain the second-stage two-stage discharge alkaline solution and the second-stage two-stage tail gas. S604. The sodium-containing alkaline solution in the third boundary zone and the second-stage tail gas are subjected to a second-stage tertiary injection to obtain a second-stage tertiary discharge alkaline solution and purified tail gas. S605. The second-stage primary effluent alkaline solution, the second-stage secondary effluent alkaline solution, and the second-stage tertiary effluent alkaline solution are mixed to obtain a secondary effluent alkaline solution; wherein, a portion of the secondary effluent alkaline solution is returned to the second-stage primary spraying, second-stage secondary spraying, or second-stage tertiary spraying steps and recycled as the boundary sodium-containing alkaline solution. S606. The remaining secondary effluent alkaline solution is returned to the third neutralization reaction and reused as a tertiary circulating alkaline solution.

[0128] The temperature of the first gas-liquid contact section in the first neutralization reaction is 65℃, the pressure of the first gas-liquid contact section in the first neutralization reaction is 0.600MPa, and the reaction time of the first gas-liquid contact section in the first neutralization reaction is 10.0 seconds. The temperature of the second gas-liquid contact section in the second neutralization reaction is 65℃, the pressure of the second gas-liquid contact section in the second neutralization reaction is 0.599MPa, and the reaction time of the first gas-liquid contact section in the first neutralization reaction is 12.5 seconds. The temperature of the third gas-liquid contact section in the third neutralization reaction is 70℃, the pressure of the third gas-liquid contact section in the third neutralization reaction is 0.598MPa, and the reaction time of the first gas-liquid contact section in the first neutralization reaction is 15.0 seconds.

[0129] The temperature of the steam contact section 141 during stripping is 116.3℃, and the stripping pressure is 0.597MPa.

[0130] The temperature of the two-stage primary injection, the two-stage secondary injection, and the two-stage tertiary injection is 67℃. The pressure of the two-stage primary injection, the two-stage secondary injection, and the two-stage tertiary injection is 0.80MPa, and the reaction times of the two-stage primary injection, the two-stage secondary injection, and the two-stage tertiary injection are 0.05s, 0.12s, and 0.25s, respectively.

[0131] In a combined reaction section, the mass flow rate of the first-stage secondary sodium-containing alkaline solution in the first-stage secondary circulation pump 31 is 5000.00 kg / h, maintaining the pH value of the first-stage secondary effluent alkaline solution at 10.1; the mass flow rate of the first-stage tertiary sodium-containing alkaline solution in the first-stage tertiary circulation pump 32 is 4500.00 kg / h, maintaining the pH value of the first-stage secondary effluent alkaline solution at 10.9.

[0132] In the two-stage combined reaction section, the secondary discharge alkaline solution is returned by the secondary circulation pump 33 to form the secondary primary circulation alkaline solution, the secondary secondary circulation alkaline solution, and the secondary tertiary circulation alkaline solution. The mass flow rate of the secondary primary circulation alkaline solution is 5000 kg / h, the mass flow rate of the secondary circulation alkaline solution is 4000 kg / h, and the mass flow rate of the secondary tertiary circulation alkaline solution is 1000 kg / h.

[0133] The mass flow rate of the sodium-containing alkaline solution in the first boundary zone is 1659.66 kg / h; The mass flow rate of the sodium-containing alkaline solution in the second boundary zone is 1161.76 kg / h; The mass flow rate of the sodium-containing alkaline solution in the third boundary zone is 497.89 kg / h.

[0134] Example 2 Compared to Example 1, the differences in this example are as follows, while the rest are the same: Based on the apparatus of Example 1, an ammonia absorption tower and an ammonia distillation tower are added.

[0135] Inside the ammonia absorption tower, the ammonia adsorbent (deionized water or deoxygenated water) comes into countercurrent contact with the purified tail gas, absorbing the ammonia component in the purified tail gas to obtain ammonia water and deionized tail gas. The obtained ammonia water enters the ammonia distillation column. Through the refining and distillation process of the ammonia distillation column, the trace amounts of hydrogen sulfide and light hydrocarbons contained in the ammonia water move as light components to the top of the ammonia distillation column and are distilled out at the top.

[0136] Example 3 Compared to Example 1, the differences in this example are as follows, while the rest are the same: The mass flow rate of the first-stage circulating alkaline solution in the second stage is 10,000 kg / h, the mass flow rate of the second-stage circulating alkaline solution in the second stage is 8,000 kg / h, and the mass flow rate of the third-stage circulating alkaline solution in the second stage is 2,000 kg / h.

[0137] The mass flow rate of the sodium-containing alkaline solution in the first boundary zone is 1109.66 kg / h; The mass flow rate of the sodium-containing alkaline solution in the second boundary zone is 1161.76 kg / h; The mass flow rate of the sodium-containing alkaline solution in the third boundary zone is 1047.89 kg / h.

[0138] Comparative Example 1 Compared to Example 1, the differences in this comparative example are as follows, while the rest are the same: The designed sodium hydrosulfide production unit uses a separate sodium hydrosulfide stripping tower. The structure of the sodium hydrosulfide stripping tower is the same as that disclosed in CN117163923A. It is used to strip and separate impurities such as ammonia and oil carried in the sodium hydrosulfide solution. In addition, the unit is equipped with pipelines and control instruments connecting the sodium hydrosulfide reactor and the sodium hydrosulfide stripping tower.

[0139] Comparative Example 2 Compared to Example 1, the differences in this comparative example are as follows, while the rest are the same: Comparative Example 2: Sodium hydrosulfide production unit. The process flow of this unit is the same as that disclosed in CN221267675U. It employs a two-stage reactor group equipped with a primary reactor, a primary separator, a secondary reactor, a secondary separator, a tertiary reactor, and a tertiary separator. In the primary reactor, the raw material undergoes a primary reaction to obtain primary reactants. These primary reactants are then sent to the primary separator for gas-liquid separation, yielding primary separated gas and primary separated liquid. The separated primary separated gas undergoes a secondary reaction in the secondary reactor to obtain secondary reactants and secondary separated liquid. The secondary reactants are then sent to the secondary separator for gas-liquid separation to obtain secondary separated gas. The separated secondary separated gas undergoes a tertiary reaction in the tertiary reactor to obtain tertiary reactants. These tertiary reactants are then sent to the tertiary separator for gas-liquid separation, yielding purified gas and tertiary separated liquid. The primary, secondary, and tertiary separated liquids from the primary, secondary, and tertiary separators are mixed and then fed into a subsequent purification unit for further processing.

[0140] Relevant experimental and effect data: 1. The equipment investment and equipment footprint of Example 1, Comparative Example 1, and Comparative Example 2 were estimated, and the results show: Compared to Example 1, Comparative Example 1 uses a conventional sodium hydrosulfide stripping tower, while Example 1 effectively reduces the amount of connecting pipes and control instruments between equipment by stacking stripping zone 14, a first-stage reaction zone 11, a second-stage reaction zone 12, and a third-stage reaction zone 13, and simplifies the reaction and treatment process of hydrogen sulfide acid gas and sodium alkali solution.

[0141] Under the same sodium hydrosulfide production requirements, compared with Comparative Example 1, the overall system investment cost of Example 1 was reduced by 9.6%, and the equipment footprint of the overall system of Example 1 was reduced by 11.7%.

[0142] Compared to Example 1, the two-stage reactor group used in Comparative Example 2 has the same function as the two-stage combined reaction section in Example 1. However, Example 1 uses a partitioned design within the horizontal gas-liquid separator by setting a first partition 241 and a second partition 242, while Comparative Example 2 requires three separate devices: a primary separator, a secondary separator, and a tertiary separator. Therefore, compared to Comparative Example 2, Example 1 can reduce the number of connecting pipes and control instruments between different devices in the system, simplify the reaction process of the two-stage combined reaction section, and reduce the floor space required.

[0143] Under the same sodium hydrosulfide production requirements, compared with Comparative Example 2, the overall plant investment cost of Example 1 was reduced by 11.9%, and the equipment footprint of the overall system of Example 1 was reduced by 17.6%.

[0144] 2. Production of additional ammonia products: Example 2 shows that by introducing an ammonia absorption tower and an ammonia distillation tower, ammonia in the purified tail gas can be separated and purified, and finally a refined ammonia water product with a mass flow rate of 5500 kg / h, a mass fraction of 25%, and a mass fraction of evaporation residue of ≤0.15% can be obtained; the main indicators of the refined ammonia water product meet the standard of "Industrial Ammonia Water" (HG / T 5353-2018).

[0145] 3. Differences in exhaust gas purification: The material conditions in each device in the system provided in Example 1 are shown in Table 1.

[0146] Table 1. Material distribution of each device in Example 1

[0147] As shown in Table 1, after treating the hydrogen sulfide-containing acidic gas using the system of Example 1 of this application, a sodium hydrosulfide product with a mass flow rate of 4735.28 kg / h can be obtained. The sodium hydrosulfide product contains 38.2302% sodium hydrosulfide, 0.0059% sodium sulfide, and 0.0795% sodium bicarbonate. The sodium hydrosulfide product meets the requirements of GB / T 23937-2020 "Industrial Sodium Hydrosulfide". Additionally, purified tail gas with a hydrogen sulfide molar fraction of 0.0028% can be obtained. After incineration, the purified tail gas meets the requirements of GB 31570-2015 "Emission Standard of Pollutants for Petroleum Refining Industry", with a sulfur dioxide content ≤100 mg / Nm³. 3 The emission limits are required.

[0148] Example 3 optimizes the mass flow rates of the two-stage primary circulating alkaline solution, the two-stage secondary circulating alkaline solution, the two-stage tertiary circulating alkaline solution, the sodium-containing alkaline solution in the first boundary zone, and the sodium-containing alkaline solution in the third boundary zone of the two-stage combined reaction section, which can reduce the molar concentration of hydrogen sulfide in the purified tail gas to as low as 0.0007%.

[0149] In summary, the system for preparing high-purity sodium hydrosulfide provided in this application integrates product purity control and exhaust gas environmental protection control strategies into the same vertical reaction separation device 1. Combined with the circulation system of the first-stage circulation section, the generation of impurities is controlled through the main reaction in the steam contact section 141, the first gas-liquid contact section 111, the second gas-liquid contact section 121, and the third gas-liquid contact section 131. Then, the horizontal gas-liquid reactor 2 of the second-stage combined reaction section deeply absorbs and removes hydrogen sulfide. In conjunction with the recycling of sodium-containing alkaline solution introduced by the boundary sodium-containing alkaline solution inlet pipe 8 of the second-stage circulation section, the external impurities of the sodium-containing alkaline solution are reduced. This precisely controls and prevents the reaction imbalance between the sodium-containing alkaline solution introduced by the boundary sodium-containing alkaline solution inlet pipe 8 and the acidic gas discharged from the first-stage combined reaction section. Ultimately, the preparation of high-purity sodium hydrosulfide and the purification of exhaust gas emissions with low hydrogen sulfide content are achieved simultaneously. Moreover, no additional impurity removal reagents or exhaust gas treatment agents are required, which conforms to the design concept of green chemical industry.

[0150] In addition, the system for preparing high-purity sodium hydrosulfide provided in this application embodiment can effectively remove impurities such as oil and ammonia from sodium hydrosulfide liquid products. It has the characteristics of high resource utilization, high selectivity of sodium hydrosulfide, simple process, flexible operation, low equipment investment cost, small equipment footprint, and short equipment operation process.

[0151] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A system for preparing high-purity sodium hydrosulfide, said system using hydrogen sulfide-containing acidic gas as raw material, characterized in that, The system includes: A combined reaction section includes a vertical reaction separation device, a steam contact section, a first gas-liquid contact section, a second gas-liquid contact section, and a third gas-liquid contact section. The steam contact section is located at the bottom of the vertical reaction separation device. The first gas-liquid contact section is located above the steam contact section, the second gas-liquid contact section is located above the first gas-liquid contact section, and the third gas-liquid contact section is located above the second gas-liquid contact section. This divides the internal space of the vertical reaction separation device into a stripping zone, a first-stage reaction zone, a second-stage reaction zone, and a third-stage reaction zone. The vertical reaction separation device includes a feed inlet for conveying hydrogen sulfide-containing acidic gas, and the feed inlet is located on the lower side wall of the first-stage reaction zone. A circulation section includes a primary sodium-containing alkaline solution inlet, a secondary sodium-containing alkaline solution inlet, a tertiary sodium-containing alkaline solution inlet, a secondary circulation pump, and a tertiary circulation pump. The primary sodium-containing alkaline solution inlet is located at the upper end of the first gas-liquid contact section, the secondary sodium-containing alkaline solution inlet is located at the upper end of the second gas-liquid contact section, and the tertiary sodium-containing alkaline solution inlet is located at the upper end of the third gas-liquid contact section. The liquid inlet is used to introduce sodium-containing alkaline solution into the first-stage reaction zone, the second-stage reaction zone, and the third-stage reaction zone, respectively; the liquid inlet of the first-stage second-stage circulating pump is connected to the liquid outlet of the first-stage second-stage reaction zone, the first-stage sodium-containing alkaline solution inlet, and the second-stage sodium-containing alkaline solution inlet of the vertical reaction separation device; the liquid inlet of the first-stage third-stage circulating pump is connected to the liquid outlet of the first-stage third-stage reaction zone, and the liquid outlet of the first-stage third-stage circulating pump is connected to the first-stage second-stage circulating alkaline solution inlet and the first-stage third-stage sodium-containing alkaline solution inlet; The two-stage combined reaction section includes a horizontal gas-liquid reactor, a first partition, a second partition, a second-stage primary gas chamber, a second-stage secondary gas chamber, a second-stage tertiary gas chamber, a second-stage primary ejector, a second-stage secondary ejector, a second-stage tertiary ejector, and a liquid collection chamber. The first partition and the second partition divide the horizontal gas-liquid reactor into a two-stage primary reaction zone, a two-stage secondary reaction zone, and a two-stage tertiary reaction zone. The air inlet of the second-stage primary ejector is connected to the top air outlet of the vertical reaction separation device, the discharge outlet of the second-stage primary ejector is connected to the feed inlet of the second-stage primary reaction zone, and the air outlet of the second-stage primary reaction zone is connected to the liquid collection chamber. The air inlet of the second-stage primary gas tank is connected to the air inlet of the second-stage secondary ejector. The outlet of the second-stage secondary ejector is connected to the inlet of the second-stage secondary reaction zone. The outlet of the second-stage secondary reaction zone is connected to the air inlet of the second-stage secondary gas tank. The outlet of the second-stage secondary gas tank is connected to the air inlet of the second-stage tertiary ejector. The outlet of the second-stage tertiary ejector is connected to the inlet of the second-stage tertiary reaction zone. The outlet of the second-stage tertiary reaction zone is connected to the air inlet of the second-stage tertiary gas tank. The liquid collection bag is located in the middle of the bottom of the horizontal gas-liquid reactor. The two-stage circulation section includes a boundary sodium-containing alkaline solution inlet pipe and a two-stage circulation pump. The outlet of the boundary sodium-containing alkaline solution inlet pipe is simultaneously connected to the inlet of the first-stage ejector, the inlet of the second-stage ejector, and the inlet of the third-stage ejector. The inlet of the two-stage circulation pump is connected to the outlet of the liquid collection bag, and the outlet of the two-stage circulation pump is connected to the inlet of the first-stage ejector, the inlet of the second-stage ejector, the inlet of the third-stage ejector, and the inlet of the third-stage reaction zone.

2. The system according to claim 1, characterized in that, The combined reaction section further includes: a downcomer, a first riser, and a second riser. The downcomer is fixedly connected between the steam contact section and the first primary reaction zone. The first riser is fixedly connected between the first primary reaction zone and the second secondary reaction zone. The second riser is fixedly connected between the second secondary reaction zone and the third tertiary reaction zone.

3. The system according to claim 2, characterized in that, The vertical distance between the bottom end face of the downcomer and the top end face of the steam contact section is 100mm to 300mm; and / or The height difference h1-h2 between the length h1 of the first riser pipe located inside the first stage of the secondary reaction zone and the highest liquid level h2 inside the first stage of the secondary reaction zone is 100mm to 300mm; and / or The height difference h3-h4 between the length h3 of the second gas riser pipe located inside the first stage of the three-stage reaction zone and the highest liquid level h4 inside the first stage of the three-stage reaction zone is 100mm to 300mm.

4. The system according to claim 2, characterized in that, The combined reaction section further includes: a first rainproof cap and a second rainproof cap, wherein the first rainproof cap is fixedly connected above the first air riser, and the second rainproof cap is fixedly connected above the second air riser. The bottom outer diameter of the first rainproof cap is 1.2 to 1.4 times the outer diameter of the first air riser, and the bottom outer diameter of the second rainproof cap is 1.15 to 1.35 times the outer diameter of the second air riser.

5. The system according to claim 2, characterized in that, The cross-sectional area of ​​the first riser pipe is 15% to 35% of the cross-sectional area of ​​the vertical reaction separation device; and / or The cross-sectional area of ​​the second riser pipe is 15% to 35% of the cross-sectional area of ​​the vertical reaction separation device.

6. The system according to claim 1, characterized in that, The circulation section further includes a secondary cooler, a tertiary cooler, and a product cooler. The secondary cooler is connected in series to the outlet of the secondary circulation pump, the tertiary cooler is connected in series to the outlet of the tertiary circulation pump, and the product cooler is connected in series to the outlet of the vertical reaction separation device.

7. The system according to claim 1, characterized in that, The combined reaction section also includes a demister, which is fixedly connected to the top of the vertical reaction separation device.

8. The system according to claim 1, characterized in that, The two-stage combined reaction section also includes a two-stage cooler, which is connected in series to the outlet of the two-stage circulating pump.

9. The system according to claim 1, characterized in that, The system also includes: The control unit includes a level controller, an online hydrogen sulfide analyzer, a boundary alkaline solution mass flow regulating valve, and a secondary discharge alkaline solution mass flow control valve. The level controller is installed inside the horizontal gas-liquid reactor to control the alkaline solution level in the reactor. The online hydrogen sulfide analyzer is installed at the outlet of the second-stage tertiary gas manifold. The boundary alkaline solution mass flow regulating valve is installed at the outlet of the boundary sodium-containing alkaline solution inlet pipe. The secondary discharge alkaline solution mass flow control valve is installed at the outlet of the second-stage circulating pump. The secondary discharge alkaline solution mass flow control valve is connected to the level controller via an electrical signal, and the online hydrogen sulfide analyzer is connected to the boundary alkaline solution mass flow regulating valve via an electrical signal.

10. The system according to claim 1, characterized in that, The two-stage combined reaction unit further includes: a two-stage primary distributor, a two-stage primary baffle, a two-stage secondary distributor, a two-stage secondary baffle, a two-stage tertiary distributor, and a two-stage tertiary baffle; the two-stage primary distributor is fixedly connected to the discharge port end of the two-stage primary injector, the two-stage primary baffle is fixedly connected to the inlet end of the two-stage primary air manifold, and the discharge port end face of the two-stage primary distributor is spaced apart from the vertical face of the two-stage primary baffle; the two-stage secondary distributor is disposed on the two-stage primary air manifold... The discharge port end of the second-stage injector is provided with a second-stage baffle located at the air inlet end of the second-stage air manifold, and the discharge port end face of the second-stage distributor is spaced apart from the vertical surface of the second-stage baffle; the third-stage distributor is provided at the discharge port end of the second-stage injector, and the second-stage baffle is located at the air inlet end of the second-stage air manifold, and the discharge port end face of the third-stage distributor is spaced apart from the vertical surface of the second-stage baffle.

11. The system according to claim 10, characterized in that, The discharge direction of the two-stage primary distributor is at an angle of 30° to 60° to the vertical plane of the two-stage primary baffle; and / or The discharge direction of the two-stage secondary distributor is at an angle of 30° to 60° to the vertical plane of the two-stage secondary baffle; and / or The discharge direction of the two-stage three-stage distributor is at an angle of 30° to 60° to the vertical plane of the two-stage three-stage baffle.

12. The system according to claim 1, characterized in that, The bottom of the first partition and the second partition are respectively provided with slots so that the sodium-containing alkaline solution in the two-stage primary reaction zone, the two-stage secondary reaction zone and the two-stage tertiary reaction zone can flow through the slots; the opening angle of the slots is 30° to 120°.

13. A method for preparing high-purity sodium hydrosulfide, characterized in that, The method is adapted to the system according to any one of claims 1 to 12, and the method includes: A first-stage sodium-containing alkaline solution and a hydrogen sulfide-containing acidic gas are subjected to a first neutralization reaction to obtain a first-stage pure gas and a first-stage effluent alkaline solution. A second neutralization reaction is carried out between a secondary sodium-containing alkaline solution and the first purified gas to obtain a second purified gas and a secondary effluent alkaline solution. A portion of the secondary effluent alkaline solution is returned to the first neutralization reaction and recycled as the primary sodium-containing alkaline solution. A third neutralization reaction is carried out between a first-stage tertiary sodium-containing alkaline solution and a second-stage purified gas to obtain a third-stage purified gas and a first-stage tertiary effluent alkaline solution. A portion of the first-stage tertiary effluent alkaline solution is returned to the second neutralization reaction for recycling as the first-stage secondary sodium-containing alkaline solution. Another portion of the first-stage tertiary effluent alkaline solution is returned to the third neutralization reaction for recycling as the first-stage tertiary sodium-containing alkaline solution. The first-stage alkali solution, all the remaining second-stage alkali solution, and all the remaining third-stage alkali solution are mixed to obtain the first-stage alkali solution. The primary effluent alkaline solution is stripped to obtain a sodium hydrosulfide solution; The sodium-containing alkaline solution in the boundary area and the third purified gas are subjected to a two-stage multi-stage injection to obtain a secondary output alkaline solution and purified tail gas.

14. The method according to claim 13, characterized in that, The temperatures of the first, second, and third neutralization reactions are all between 50°C and 75°C, the pressures of the first, second, and third neutralization reactions are all greater than or equal to 0.10 MPa, and the times of the first, second, and third neutralization reactions are all between 0.5 s and 90 s.

15. The method according to claim 13, characterized in that, The stripping temperature is between 110°C and 185°C, and the stripping pressure is greater than or equal to 0.10 MPa.

16. The method according to claim 13, characterized in that, The process of subjecting the sodium-containing alkaline solution in the boundary area and the third purified gas to a two-stage multi-stage injection to obtain a secondary effluent alkaline solution and purified tail gas includes the following steps: The sodium-containing alkaline solution in the boundary area is divided into the first boundary area sodium-containing alkaline solution, the second boundary area sodium-containing alkaline solution and the third boundary area sodium-containing alkaline solution. The sodium-containing alkaline solution in the first boundary area and the third pure gas are subjected to a two-stage first-stage injection to obtain a two-stage first-stage discharge alkaline solution and a two-stage first-stage tail gas. The sodium-containing alkaline solution in the second boundary zone and the first-stage tail gas in the second stage are injected in a second stage to obtain a second-stage discharge alkaline solution and a second-stage tail gas. The sodium-containing alkaline solution in the third boundary zone and the second-stage tail gas are subjected to a second-stage tertiary injection to obtain a second-stage tertiary discharge alkaline solution and purified tail gas. The two-stage primary effluent alkaline solution, the two-stage secondary effluent alkaline solution, and the two-stage tertiary effluent alkaline solution are mixed to obtain a secondary effluent alkaline solution; wherein, a portion of the secondary effluent alkaline solution is returned to the two-stage primary spraying, the two-stage secondary spraying, or the two-stage tertiary spraying step to replace the sodium-containing alkaline solution in the boundary area for recycling. All remaining secondary effluent alkaline solution is returned to the third neutralization reaction and recycled as a first-stage tertiary sodium-containing alkaline solution.

17. The method according to claim 16, characterized in that, The temperatures of the two-stage primary injection, the two-stage secondary injection, and the two-stage tertiary injection are all between 50°C and 75°C, the pressures of the two-stage primary injection, the two-stage secondary injection, and the two-stage tertiary injection are all between 0.3MPa and 3.5MPa, and the reaction times of the two-stage primary injection, the two-stage secondary injection, and the two-stage tertiary injection are all between 0.01s and 0.3s.

18. The method according to claim 16, characterized in that, The mass flow rate of the sodium-containing alkaline solution in the first boundary region is 0.4 to 0.6 times the mass flow rate of the sodium-containing alkaline solution in the boundary region; and / or The mass flow rate of the sodium-containing alkaline solution in the second boundary region is 0.3 to 0.5 times that of the mass flow rate of the sodium-containing alkaline solution in the boundary region; and / or The mass flow rate of the sodium-containing alkaline solution in the third boundary region is 0.1 to 0.4 times that of the mass flow rate of the sodium-containing alkaline solution in the boundary region.

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